Hi dear,
Most probably your condition is not serious, you could be having common
throat infection or
cold, sometimes you can have mild infection with
fever without obvious symptoms. The lower right
back pain could be unrelated to the fever you have, it could be due some activities you did that caused you the pain.
However you should remember that fever with back pain could indicate that there is infection in your back or kidneys and must be seen and evaluated by a doctor.
Unfortunately in your question you haven't included how long you had this condition so i cant reach to a better conclusion. Therefore read below for my suggestion.
If you had fever and back pain for 5 days or more with no any betterment of the symptoms then visit Doctor immediately.
If you got fever and back pain about a day or two days ago then start taking
Paracetamol 500mg 4 times a day and continue for 3 days, if your fever and pain doesn't reduce with taking paracetamol or you still have fever after 3 days of taking the medicine then visit a Doctor.
Wishing you all the best