I guess, this is because of scar tissue touching nerves. It will take time to heal. Interventional therapy is good option for reducing pain temporarily.
I had this happen to me after my neck surgery. I was having right side pain, and they fused my C5-C7. A couple years later, my left side started giving me problems. Turns out my C3-C4 were deteriorating. Doc went in and put a plate from C3-C7. I'm having pain again, but this time, Doc says it's soft tissue issues. He says there is nothing to be done about that but going to Physical Therapy and meds. You are definitely NOT alone with this type of issue.