I'm going to try to help you by explaining my own similar situation.
I knew a guy for all of my grade school years and we were really close friends. It was clear that he liked me for a long time, and I liked him but I was shy; so when eighth grade ended he asked me to a dance and I said no. Right after school ended he moved away. We kept in close touch for about a year and a half; always emailing everything about our lives. That was about 4 years ago, and I still seem to think about him every day and get that pang inside that you mentioned.
What I've learned about my feelings (and I hope I'm correct) is that we were really close, and so I miss the relationship (friendship) that we once had. I think what causes the "pang" is wondering what could have been, but didn't happen, and regretting the past decisions.
I don't think that you like guys today just to be rid of your feelings about him. I think that he was once a big part of your life, was involved with a big decision on your part, and so it is natural to think about him often, and to wonder about the circumstances he might have affected.
I hope that I helped atleast a little
