Dear Joyce44: Scar tissue can cause discomfort. However, it is impossible to know if this is the case for you. You should have your doctor look into the neck and shoulder pain. It may or may not be related to your implants. If it is discovered that your pain is unrelated to your implants, and you are having no other problems related to your implants, you might consider speaking with another plastic surgeon regarding when - or if - these need to be replaced.
I appreciate your speedy response. Regardless of whether or not my neck/shoulder pain is caused by the implants, I do need to have them replaced. One has lost volume and there is some encapsulation. I understand that 10 years is often the average "life" of implants. I have had one for 23 years and the other for about 22 years. I feel as if I am pushing things this way for too much longer. I would rather have them replaced while I am in good health and before they cause a major problem.