Thanks for writing your query.
After reading your post, it seems that your husband is having viral fever
as viral fever is commonly accompanied by myalgia
or pain in muscles. This occurs due to some biochemical changes in the muscles as a result of fever. It may persists for few days even after there is no fever. Viral fever usually takes 5-7 days for complete recovery.
Give him proper rest for speedy recovery.
Hot fomentation will help in relief of pain. Apply locally some pain relieving gel.
If the pain persists, you can give him pain killer like Ibuprofen
one tablet twice a day after meals along with an antacid
Give him healthy fluids to drink to maintain proper hydration of the body. Encourage him for taking fresh fruits and vegetables which will increase his immunity.
If the problem persists, you can get him examined by your doctor.
Also get him investigated for Complete Blood Count
and serum electrolytes and urine examination, to know the cause of fever.
I hope this is helpful to you.