Is surgery mandatory for a muscle tear?

Hello doctor,

I suffered an injury in the right shoulder region four months back by falling off a fast speedboat. I was wearing a life jacket and buckles on impacted shoulder and I believe my arm was pulled back. It bruised badly. It is painful in some range of motions and have started back at the gym and hurts when under load on an exercise like pec dec. I went to an osteopath who reported below:

During an examination, there was pain on lateral flexion of his right shoulder. On observation, during right lateral flexion of the shoulder, his pectoralis looked atrophied and unsymmetrical compared to the left. On palpation, he was very tender on his right pectoralis major tendon and lateral muscle belly. I have therefore diagnosed him with a right pectoralis major tendon and muscle tear.

I have just received results from an MRI. My questions are:

What treatment should be done? Should I continue to exercise and slowly build up weights? Would it require surgery?