Tightness in eyelid post-op
Occasional tightness for 15 years after a congenital ptosis repair surgery is nothing to worry about. Probably a little dryness. As long as you are happy with the lid height, and everything else seems ok with vision etc. there is nothing else you can do to eliminate the sensation.
Really need photos and an examination to understand the full extent of your problem. At this point I could not suggest a surgical correction.
Tight Eyelids Following Congenital Ptosis Repair
There are different ways to repair congenital ptosis. The thing to keep in mind is that congenital ptosis eyelids are never quite normal even if they can surgically be lifted to help one see better. The tendon that opens the eyelid is often very fatty infiltrated and not healthy. Therefore the surgery to correct the ptosis is more extensive than most acquired forms of blepharoptosis and can leave the eyelid more "tight" and having issues with eyelid closure. I would see an ophthalmologist or oculoplastic surgeon for an in person consultation. In general if your eyelids are opening well, and you are not suffering dry eye problems then leaving them alone is optimal as the more surgeries your eyelid undergoes the longer the healing and more potential for complications.