Being a couple months away from being a physical therapist (as well as being addicted to this website since 2000) I can tell you from most cases a person just starting on a workout program, really getting into it, then hurting yourself, is generally easy to fix. I have been there myself, and can tell you it is going to suck during the rehab process, but mostly because you have to lay off and let the tissue heal. You can still exercise, but do other things.
Example: I have impingement syndrome in the right shoulder and a first degree labral tear in the left shoulder. I'm fuckin' bummed because I was really getting into olympic lifting, and this is causing a couple complications, but I'm making up for it in the meantime with a pilates at school. Its great because it allowed me to really hone in on my overall weaknesses that I acn address before trying to build up muscle on a potentially unstable frame. Plus there are a lot of hot chicks that are in to exercise there!
Back to important stuff: As has been stated on this site numerous times, don't allow a single incident of a medical professional's misguided actions, be it MD/DC/PT etc, lead you to believe the entire profession is lacking worth. Along those same lines, not all medical professionals specialize in athletic injuries. I would personally go to my primary care physician if I was ill, however, for musculoskeletal/neuromuscular patholgy, even he knows I can take care of my self and diagnose myself better than he can. That is not because he doesn't know what he is doing, but he is just trusting the judgement of a person who specializes in a particular field. When you received your physical therapy, you may not have had the best PT in relation to weight lifting injuries. Conversely, you may not have been sticking with the appropriate dosage of exercise during an alloted time frame. This really is a multi-facted issue here. Hopefully this can give you a little insight into the world of the people who take care of you.