Trunk Not Level??

I've been noticing some noise while driving which seems to be coming from the rear of the car, I think it's the trunk?? It seems to be moving a little while driving, but not sure if this is the problem. With the lid open it seems to have a little play in the right side corner. Is there anyway to adjust this? Also, I looked at the seal to see if maybe it is worn on that side alowing for the lid to move but can't really tell if it's bad..there are no cracks and it doesn't leak but it still might be a little flat allowing for the trunk to move..does that sound like an answer?? How easy is the seal to replace?? Do you have to use any gasket sealer or anything? The trunk lid is in great condition, so I don't want to replace it but need to make an adjustment on it somehow? Any sugestions?