Thank you guys.... I really do appreciate your insights and i feel better about the hand now 
To answer all your questions...
1. He might have missplayed his overpair somehow, thats true. The problem is, i see him multitabling everytime i play. I know he is solid player and i got some history with him.
Im pretty sure he is aware of the fact that im solid player as well..
and since i open limp MP i simply cant have any other hand to go broke with on this flop than 55 or 33.
So thats why i asume he wouldnt go broke for 150bbs with his overpair againts another regular who limped MP.
One thing that made me call is that he tried to bluff me all in in the past, but it was different situation and i dont think he would try to bluff my so obvious set.
When i got the set and he did bet on the flop, i raised thinking to myself "hmm and now he folds because he knows i got a set...."
2. The reason why I 4bet and didnt push is that we were deep and the pot was very small on the flop. I was thinking about pushing after he 3bet, but i dont think it would make any difference.
I had 18$ of my 30$stack left after 4bet.
3. Yep i play NL20 and i know its not some pro limit, but as i said the villain is solid regular.
Anyway i appreciate your replies.
I felt really bad after this hand. I dont care about set vs set or other cooler situations anymore, because i know next time its gonna be me with the nuts.
But i feel bad when im not sure if i could have avoided it by playing better.
Suckouts are fine, but not being sure about my play is killing me