Corner loading/left louder ?

If you can I'd pull the speakers another foot or even another two feet into the room if you haven't already done so and see what happens.  It might help and you may find an improvement in imaging and soundstaging although probably at the expense of some bass loading, which may be part of the problem.  I'd also experiment with toe in -- maybe try crossing the speakers a bit in front of you if you haven't already done that yet either.  As suggested you can use the balance control if you have one, but I find this can sometimes compromise sound quality.  If you have the flexibility you could also try placing the speakers so they flank the corner (so the corner would be midway between the speakers).  I've seen this done at audio shows to help mitigate smaller or irregularly shaped rooms.  In all seriousness and if positioning doesn't help at all, you might consider getting your hearing checked just to rule that out.  Best of luck. 

The speakers have two ports in the back, which also came with foam port plugs, which speaker should I plug with the plugs? Or are the port plugs for something different ????

plug the right side (which has the louder sound??)
top or bottom port?

will this limit my loudness, making one speaker accept less power from the amp, possibly damaging it at loud volume??

arcticdeth -
I sympathize.  For whatever reason channel imbalance makes me crazy.  I don't know why it can bug me so much.  If you have a balance contral, by all means use it.  BUT first if it were me, I'd be reversing speaker cables at the amp to see if the louder speaker remains on the right.  That should eliminate a component problem as the cause.  For me, knowing it was not gear would make me a lot less anxious.  The room is what the room is.  If you have a mono recording, maybe use that and the balance control to get things centered.  This is NOT to dismiss other suggestions about positioning speakers differently if that can be done.  Experiment with the foam port plugs too.  Seems like using them on the right would be the way to go (intuitively) but upper or lower? can't say.  You would have to experiment.  Hope this helps.  Good luck.

PS - Any way you can put a bi-folding decorative panel(s) behind and to the side of the left speaker?  If it is room asymmetry, maybe that would help.  Something lightweight you could move out of the way when not listening to music.