If you can do overhead pressing without pain, keep that up.
Do a light, light, light movement like cable pec flies to keep blood flow going to the area. Eat well, sleep well, drink lots of water, and get some soft tissue work done on the area. Foam rolling is good, ART would be better. Pain is bad.
I've had a similar problem and now, after a 5 week lay-off of horizontal pressing, I'm able to do pain-free light benching and band pushups.
To get back into things, I'm going to reteach myself how to bench with an exaggerated 'tear the bar apart' queue, strengthen my tris like nuts, and widen my bench press grip width so my pec isn't stretched so much at the bottom of the movement.
Take it slow getting back into things. When you get back at it, pay particularly close attention to bar speed on both sides. For me, my right side bar speed was slower than my left, so my right pec had to do more work and eventually gave way.
Give it time and you'll be back at it. Good luck