Exercises for shoulder injured client

My client experiences pain in his shoulder sometimes it actually locks up when we're doing exercises such as overhead press, push ups even a bicep a curl or tricep dip's. He doesn't want to see a physical therapist which would help me figure out what exercises would be contradictory. He literally will hit it and says that he feels that that unlocks the shoulder this is been going on with him for over 10 years. I worked on mobility with TRX and no wait over 5 pounds. I'm trying to determine what exercises I should not do with him and what exercises I could do with him that would increase his strength without exacerbating the situation. I feel very limited in my knowledge in this area and try to attend appointments with my other clients to actually do you see physical therapist but each client is an individual and age for their situations are individual. What class or CERT could I take to help me increase my knowledge of exercises that would be indicated in contraindicated and what would you do if this was your client? I know we should not diagnosed as personal trainers.