No pain No Gain?

I have been getting back into martial arts and have been loving it. I train at one of the best gyms in the Portland metro area Impact Jiu-Jitsu. Many fighters that come out of this gym are ranked number one in the local MMA scene. Last night I was thrown and landed on my shoulder when I hit the mat I heard and felt a small pop. I was sparring so I thought my arm can still move so keep going. Well I was awakened in the middle of the night from the pain in my shoulder. Keep in mind this was after taking a handful of pain meds before bed. Before getting back into martial arts I knew that I was eventually going to injure something. I just didn't think I would be so soon. It's really really frustrating to me that my body isn't as durable like it use to be when I was 18. It has been great getting to wrestle again. I plan on getting into competitions in a year of so if not sooner. I don't think I will get into any MMA bouts cause I don't like getting punched in the face but I am training MMA to shed more pounds off.