Shoulder Pain - Multiple Issues

I am a 51 year old male triathlete with a desire to compete in Ironman distances. I am experiencing some shoulder pain. I've had two episodes since June where pain has been acute at a 7 to 8 on a scale of 1 to 10 with 10 being extreme pain. In between episodes, shoulder aches. After second episode, I sought medical assistance via primary physician. Sent me for x-rays. X-rays showed calcific tendonitis (?). Was referred to orthopedic surgeon. Orthopedic surgeon said I had artheritis in the A/C Joint, 2 bone spurs on the acromion, and calcium deposits the circumference of a dime and 1/4" thick. Orthopedic surgeon gave me a cortizone shot. Seemed to ease the pain for about 6 or 7 days and pain returned. I regained most of the range of motion except when I cross my arm across my chest (like I was scratching the opposite arm). Pain is now intermittent. Some days I experience pain at a 2 to 4 on scale of 1 to 10 with 10 being extreme pain. I have avoided any activities that involve raising arm above the shoulder.

Is this impingement or another issue?
With the multiple issues, will physical therapy ease the pain?
Should I let the doc give me additional cortizone shots?
What options do I have?