I had a specific injury that caused my tennis elbow. I had multiple cortisone & blood injections & surgery 4 mos. Ago-still have pain-any other tx?

Difficult. First, i would probably recommend a second opinion to confirm that tennis elbow is your actual diagnosis. Many doctors jump straight to injections and surgery prior to emphasizing stretching and therapy. I would definitely do these if they haven't been done. Unfortunately, there is a subset of patients who just don't respond to surgery the way that we would hope.
More detailed surger. It depends on the surgery that was done. The tried and true operation is to detach the ligament, shear off the bone spur, and reattache the ligament. More limited surgery is sometimes ineffective. Other treatments you have received are appropriate.