I was hitting the gym very hard over the course of a month, working out 5-6 times a week, alternating days between different parts of my body, staying extremely hydrated, and consuming a proper diet and protein. One day, after having a rather heavy day doing tricep extensions and bicep curls, I was messing around and tried to fall on my face and catch myself in a push up, and then push myself back up to standing. I did so. However, afterwards I had an extreme pain that hurt to move my chest, and turn my neck. the pain has been isolated to the extreme left of my right pectoral muscle (pretty much feels like its touching my sternum) and it is hard to manipulate it to make it hurt. However, it is very sensitive when it does hurt and it has been almost three weeks since the injury. I haven't touched a weight on my upperbody since the incident, when I wake up in the morning it hurts in particular just from moving around during sleep. It gets better and is not made worse by running or light activity.
What is this and how do I stretch it, work it, make it feel better.