Months after carpel tunnel surgery having trigger finger swelling pain, is it normal?

No: These are unrelated issues. It is not a complication of carpal tunnel surgery.

Common: Since the flexor tendons to the fingers co-habitate with the median nerve in the carpal tunnel, it is not rare for patients with carpal tunnel to eventually get trigger finger. Swelling post carpal tunnel release can lead to changes in the flexor tendon sheath that eventually leads to triggering. Early nsaids or steroid injection may prevent the need for surgery, but surgery is a common option.