How To Heal A Radiating Pain Felt Inside The Chest For A Person Carrying Weights?

Hi, I lift weights and have noticed a pain in the centre of my chest, slightly to the right side if anything. it feels quite deep inside. The pain is worse in the morning and sometime wakes me up in the night. I also feel the pain when I sneeze of sometimes if I move in a certain way. I can feel it to a lesser extent i I exhale fully. It has also been limiting me from doing certain exercises at gym due to uncomfort. The docters have checked my chest and said it feels clear so have guessed it to be something muscular, I have gone for massages but this has not helped, can you offer any advice? Thankyou Chris