Pain due to change in mechanics?

So I changed my mechanics from the stretch for myself to get the ball out quicker, but after 30 or so pitches my right pectoral started to get sore. I could have gone on pitching because it didn’t hurt very much but I decided to call it a day and I stopped. The next day, it barely hurt so I’m not too worried.
I’m just wondering… could this soreness just be because I changed my mechanics and my body is just getting used to it and that I just need to strengthen up my chest or is it because my mechanics still need some work?
Any help would be greatly appreciate!


You should get together with a good pitching coach and have him check you out. Let him see what you were doing before and after you changed your mechanics—and this I don’t quite understand: what made you decide to do this? Was it an overall change, or just a couple of things? And what about your arm slot? Did you make any drastic changes in this. which may have been a bad mistake? And it might be a good idea for you to post a before-and-after video so we can see just what the score is. 8)