Glad to hear the news that you're back in the gym. Unfortunately and fortunately, I don't think you hurt your job there.
TMJ problems usually start on one side. The initial injury to the TMJ normally doesn't cause any pain or symptoms. Once you start noticing dysfunction and pain in your jaw joint, it means that things are changing and not for the better.
You want some good news? It is much easier for a TMJ pain management specialist to treat early problems, such as the ones you are describing, than to treat them later after both sides are involved.
My suggestion to you is that you schedule a comprehensive TMJ examination to find out exactly what is going on and to learn your options for conservative treatment.
I'd be very interested in learning about your adolescent and teenage years regarding sports and activities that cause trauma to your head and face. Think hard about it. Quite often, trauma to your face during these years, especially when unnoticed and untreated, is the culprit. Dr. Paul