Suggest Treatment For Sinus Infection

I have a Sinus Infection and have been on Amoxicillin for three days. The sinus symptoms are improving, however I have been left with a very bad cough. About three days ago, I coughed and felt pain in my side...just below my rib cage. It is tender to the touch and is very painful when I cough or sneeze. I consulted a Dr. who said my lungs were clear so there was nothing to worry about.
The pain is very bad and I am wondering if there is anything that I could do. I have no trouble urinating.
Thanks

John