DVD drive sticking damage my DVDs?

The DVD drive on my comp takes many pushes of the open button to actually open when its empty, like 5 or more pushes.. On the first few pushes to open it, it makes the sound inside like its trying to open but doesnt, the lights do flash through every try.. But heres the wierd part, until recently when it finally did open and I watched a dvd, then on the first push to open the tray to take the dvd out, it works... BUT now suddenly its taking like 2 pushes to get it to open to take a dvd out.. So now I'm worried, when I have a dvd in there, and I push the open button but it doesnt work, (but goes through the sounds inside and flashing lights like its trying to open) am I now damaging the dvd inside with every push to open the tray that doesnt work? And why does it take many 5 or more pushes to open with no dvd inside, but then just one or now two to open when a dvd is inside?