Ok so that sharp pain I felt at the end of my session is a cracked rib. Hurts to breath deep, cough, sneeze or laugh and I cant raise my left arm above shoulder height. I've cracked my first rib, just behind my collarbone on my left hand side. Fortunately it hasn't displaced at all so it should heal quickly. I'm on orders not to lift for a month and then to ease back into things.
Plan in the mean time is to do occluded cardio, occluded bodyweight squats, lunges, core + mobility work and once there is no pain I can do pressups and reverse rows.
Do or do not, there is no try.