Sometimes I feel a sharp pain in my left chest.

It's been a while since my left arm and shoulder have been hurting. I feel numbness like a cramp, or it's difficult to rotate my arm backward and it doesn't lift up easily. Recently, I often experience a sharp pain in my left chest area. Yesterday, while driving, I felt such chest pain that I wondered if I was about to stop breathing. If the pain in my left shoulder and arm is related, I wouldn't be as worried since it's chronic pain, but I'm worried it might be due to a completely different reason.