problem?

i am a teen, and i get s whenever i come into close contact with girls, even if it is not suggestive. like this one time i was in a bed with a girl, fully clothed and we had to cuddle and take a picture and i got a hard on and it showed in the picture. how embaring. it also happens when i dance with girls: grinding, slow dancing,etc. and this one time in acting i had to put my arms around a girl and i could feel an coming but it went away because i took my arms off her. what the hell, does this happen to anyone else?