What Is Causing Pain In My Inner Thigh?

I had an inguinal sentinel lymph node biopsy three weeks ago and I am experiencing pain in my inner thigh that makes it quite painful to walk. Most of my thigh is quite tender to the touch as well as an area on the side of my hip. My surgeon is sending me to a physical therapist, but I feel there is something more. I currently have a seroma from the surgery that he is draining once a week. I'd like to get to the root of the problem because I don't feel like my surgeon is.