I found that physical therapy after back surgery is very helpful and never increased my pain. In fact, it relieved my pain. Your muscles need to be strengthened again to help support your spine and hip structure. You say you miss exercising and PT would be the best way to begin to get some of that exercise. I always started PT within two weeks of my surgery. You may feel stiff and/or sore a day or two after your PT session but it isn't long lasting.
Heat packs or a heating pad can be used to relieve your pain. Limit your sitting to no more than about 45 minutes at a time and then get up and walk, if only to get the mail or a drink of water. You should be up on your feet for at least 15 minutes each time if you can tolerate it. Also your chair needs to support your spine. A recliner or easy chair are not good choices. Your goal right now is good posture whether you are standing or sitting. The healing process takes several months and each month will be better than the last. You took the biggest step when you decided to have your surgery. Look at yourself as a partner in your recovery, not just as the patient who is trying to recover.