Muscle aches with fever are caused by a bacterial or viral infection, as in cases of colds and flu, and may also be caused by a viral gastrointestinal infection (stomach cold), pneumonia (mostly bacterial), or a urinary tract infection (bacterial). Bacterial infections can be treated with antibiotics, while viral infections are allowed to recover. Sometimes muscle pain that is not accompanied by a fever occurs due to a variety of reasons and on the basis of which treatment is decided, but in all cases there are some steps you can take to reduce the feeling of discomfort and speed up the recovery process.
Go see a doctor. Go to see a doctor if you have muscle pain and fever at the same time, in order to diagnose the cause of your symptoms and prescribe the appropriate treatment for your condition, as muscle pain accompanied by fever usually requires medical intervention.
Your symptoms may be caused by exposure to insects or ticks, causing you to develop various conditions such as Lyme infection, which requires medical intervention.
Avoid changing your medications without consulting your doctor, as this may trigger some flu-like symptoms.
Metabolic disorders should be treated by a specialist, whose symptoms appear in the form of pain in the lower extremities, which increases with exercise.
Take ibuprofen or acetaminophen (Tylenol). These over-the-counter medications reduce fever and muscle aches, as ibuprofen lowers body temperature and reduces the level of the hormone “prostaglandin” that causes pain and inflammation. Acetaminophen reduces pain by acting in the central nervous system and reduces fever, but does not reduce inflammation. You can switch between both drugs to get better results from just one use.
Do not double the dose on your own, but follow the directions that come with the medicine.
Switching between the two medicines reduces the side effects caused by taking only one medicine.
Avoid prolonged use of non-steroidal anti-inflammatory drugs, as they cause damage to the lining of the stomach, causing bleeding, inflammation of the stomach and ulcers.
Avoid giving aspirin to children. Aspirin is considered safe for adults, but it is not safe for children as it causes Reye’s syndrome, which affects the brain and liver, which is common after influenza or smallpox. As it is a serious condition that may kill his life, and you can identify the symptoms that appear on the child after taking aspirin, including: 
Nausea and vomiting.
Ask your doctor about antiviral medication in case of the flu. Ask the doctor about antiviral medications in order to shorten the duration of suffering from flu symptoms, which are usually transmitted from one person to another due to direct contact or lack of attention to hygiene. Centigrade or more, and some sufferers also suffer from upper respiratory symptoms such as headache, cold, chills, sinus pain and sore throat.
Getting an annual flu shot helps reduce your risk of infection.
Your doctor will prescribe oseltamivir if your symptoms do not last longer than 48 hours, and the drug is prescribed at a dose of 75 mg twice daily.
Take antibiotics to treat a bacterial infection.  If your doctor suspects that your symptoms are caused by a bacterial infection, the antibiotics kill the harmful bacteria and allow the body to fight off the rest of the infection naturally. Remember that antibiotics are ineffective against a viral infection.
The type of antibiotic depends on the type of bacteria you were exposed to.
Your doctor will ask you to get tested by taking a blood sample and testing it to determine the type of bacteria causing your symptoms.
Rest and take it easy.Studies have shown that sleep deprivation negatively affects the immune system while rest strengthens immunity. Your body needs rest in order for your immune system to fight off infections that cause fever and body aches, even with You take medicines.
Use lukewarm water to reduce fever. Take a lukewarm water bath or use cold compresses to reduce your body temperature due to a fever, but avoid doing this if you are shivering as the cooling will stimulate more shivering, which leads to an increase in your body temperature.
Avoid taking a cold shower to avoid a rapid drop in your body temperature, so just take a shower with lukewarm water.
Make sure you are well hydrated. Drink water in order to replace the water your body loses as a result of fever,  as dehydration becomes worse if the fever is accompanied by vomiting or diarrhea, and therefore it is necessary to drink fluids and water well in order to replace the lost and give the body the opportunity to carry out its vital functions properly.
Drink sports drinks such as Gatorade and Power Aid if you suffer from fluid loss due to digestive disorders, as these drinks replace the lost electrolytes. 
Drink fluids such as soup or broth, especially if you have vomiting or diarrhoea, and remember that it is important to replace the fluids you lose due to these symptoms.
Drink green tea in order to strengthen your immune system, but avoid drinking it in the case of diarrhea accompanied by pain and fever, as green tea makes diarrhea worse.
Eat foods rich in antioxidants. Foods rich in antioxidants help strengthen your immune system and make it easier to fight the infection causing your symptoms. Examples of these foods include: 
Blueberries, cherries, tomatoes and other dark-colored fruits.
Vegetables such as pumpkin and sweet pepper.
Avoid junk and processed foods such as donuts, white bread, French fries and sweets.
Wear wet socks for bed. This method helps reduce body temperature by wearing a pair of cotton socks moistened with lukewarm water, and then covering them with a pair of thin dry socks in order to ensure that your feet are warm.
The body stimulates blood and lymph circulation in your body during sleep in a way that stimulates the immune system.
Do this for 5 to 6 nights and then take a 2 night break before continuing.
Refrain from smoking. Smoking worsens the symptoms of viral infections in cases of colds and influenza,  and weakens the immune system in a way that reduces the body’s ability to fight infection.
Relax the stressed muscles. The most common cause of non-febrile muscle pain is fatigue, due to prolonged muscle strain during training or difficult tasks, and pain due to a build-up of lactic acid in the muscles. Lie down after exercising. In order to allow the muscles to rest, relieve pain, and then feel better.
Train regularly to prevent this type of muscle pain and to avoid shocking your body from sudden exertion, you can also do the muscle effort gradually, and pay attention to stretching exercises before and after training.
Take care to compensate for the lack of electrolytes caused by the lack of potassium and calcium, which causes muscle pain.
Drink sports drinks like Gatorade and Power Aid to replace lost electrolytes.