There can be a number of issues here..
Mine wouldn't open because my trunk was not fully closed. There is a sticky with the "soft close" problem that you may want to look at it. Is your light on the trunk latch switch on your driver's side door? There can be issues with the flaps on the trunk lid, faulty pump (hope not), but I think you should bring it to get checked out if you are not a DIYer. I do know if you pull the fuse for the trunk you may be able to get it closed, but like I said, too many things to look at but make sure your trunk is firmly closed before you move on...
Shaun