I really love my boyfriend but i have trouble showing affection towards him.?

I show him affection when were alone but we don't get the chance to be alone often. I just kind of treat him like a friend in public. But I don't think of him as one. We make out and everything when were alone. But I can't seem to treat him like were dating when were in public. I don't have problems with PDA's. I really really want to be able to show affection. I think I'm just shy. Any tips or tricks on how to fix this?