Fever with sore-throat irritation and leg/body pain is often caused by a viral infection such as flu or COVID-19, but strep throat or another infection is also possible. You cannot reliably tell the cause from symptoms alone.

Please arrange a medical review today or within 24 hours, especially if fever is persistent or high. A clinician may examine your throat and consider a throat swab, plus COVID-19/flu testing. Viruses are the most common cause of sore throat, but strep needs different treatment, so do not start antibiotics without a prescription. CDC sore-throat guidance

For now:

Get urgent care now if you have trouble breathing, chest pain, confusion, severe weakness, inability to swallow fluids or saliva, dehydration or very little urine, stiff neck, a spreading rash, fever above 39.4 C (103 F), or fever lasting more than 3 days.

Also seek urgent assessment if one leg is significantly more painful, swollen, red, or warm than the other, or if leg pain occurs with breathlessness or chest pain.

If you are pregnant, over 65, immunocompromised, or have diabetes, heart, lung, or kidney disease, contact a clinician promptly because flu/COVID treatments work best early. CDC respiratory-illness advice

Please tell me your age, temperature, how many days this has lasted, whether you have cough/runny nose, and whether the leg pain is in both legs or only one.

If you mean you have no cough, that makes a simple cold-type viral infection a little less likely and makes strep throat one possibility, especially with fever and painful throat. But it cannot be confirmed by symptoms alone. A clinician can do a quick throat swab or rapid strep test. CDC guidance on strep

Please see a doctor or clinic today or tomorrow, particularly if you have:

Do not take antibiotics on your own. They are useful only if a bacterial infection such as strep is confirmed or strongly suspected.

Until then: rest, fluids, warm salt-water gargles, and fever/pain medicine as directed on its label if safe for you.

Go urgently now if you cannot swallow saliva, have breathing difficulty, severe neck swelling/stiffness, a rash, confusion, chest pain, or one leg becomes swollen/red/warm.