transmission problem need help :(
 

i have a 1999 honda civic si.. its auto tansmission... the problem is tht if i put it on park and then try to put it on drive or reverse it gets stuck and i have to pull it hard... specially wen its parked for more than half an hour.. i wanna knw how big of a problem is it cuz i dun wanna get riped of cuz a frnd of mine had a prelude it was manual and the he had the smilar problem but it go replaced by puttin some oil which costed him 12$ and his mechanic quoted him 114$ i wuld have askd him but i have lost touch wid him and i dun no wat to do plz help..