Pulling sensation and pain in nipple?

I am almost 8 mo post op, high profile silicone 365cc under the muscle. My left breast sometimes twitches when I move my arm a certain way and when it is cold. A few months ago I noticed that I have a small dent in my lower clevage area, and when I push on the dent I can feel it in my nipple and across the whole breast, like a string is in there and pulling. Should this be a concern? My PS said a dent would go away on its own but it hasn’t at all and now I have pain too.