May implant removal stop breast pain? I had 360ccs under the muscle 4 years ago and have had pain ever since.

I'm sorry to hear of the discomfort you've been experiencing.  As your pain began with the augmentation there is a chance it will be relieved when the implants are removed.  Your surgeon should be able to tell you if there is capsular contracture present.  

patients do occasionally get chronic breast pain with implants. it seems to be more common with implants that are under the muscle.  if the implants are the cause of the pain, I would expect that the pain would resolve after the implants are removed.  I would recommend finding a board certified plastic surgeon near you and discussing your concerns with them.

I do not recommend implants
and instead I recommend explantation using The Bellesoma Method.  The implants are removed, your breast tissue
is reshaped creating upper pole fullness, elevated higher on the chest wall and
more medial to increase your cleavage. 
Vertical scars are avoided, nipple sensation and the ability to breast
feed are maintained, if not injured during your previous surgery.  At the same time or later, fat transfers can
be performed if additional volume is desired. 
No technique can guarantee elimination of your pain but removing the 360
cc implants will reduce the pressure on your nerves.     Best Wishes,Gary Horndeski, M.D.