Good luck on your recovery!!
I`m 1 year out from a left hip injury(intermuscular tear of the Hamstring and Iliopsoas, partial tear of Rectus Femoris head and posterior labrum). It is the most frustrating thing I have ever had to deal with! I broke my tib/fib when I was 7 and that was nothing compared to this! Soft tissue damage takes so much longer that bone fractures and I believe them to be more mentally damaging. It is easy to get depressed and angry when dealing with injuries, there have been many tears this past year. I did 1 round of PT and then re injured on Sherman ( damn rocks!) I had done Democrat, Lincoln, Cameron, and Bross 2 days prior and was just fine. SO I did another round of PT, to avoid surgery. I am doing very well now and I am back to running and training for a race and planning 14ers.
However, I am now in my 3rd round of PT because I have developed tendonitis in my rt ankle, from months of favoring the left leg and limping for 7 months. Definitely talk with your PT person about exercises for your non injured leg as well, so you can stay away from an over use injury! I am an MRI tech and I see these injuries a lot, they are like domino's and 1 injury can turn into another.
As far as how to know what is good pain vs bad pain, it very hard to tell, it will take some trial and error. It is so nice the first time you wake up and are sore from a good work out rather than in pain from injury!!! if my hip hurts from looking at a picture of an exercise I don`t do it or I modify it. Gradually work toward things, it will be months before I do a lunge in public bc I look so pathetic doing them, but I will get there eventually and thats all that matters.
Hang in there, it can only get better!
Be yourself, because everyone else is taken.