Hi,
Two nights ago I left my GS on center stand over night with front wheel on the ground and rear wheel off the ground. Ever since, handle bar feels so heavy. Turning the handle bar needs a lot of power and is stiff and feels tight. I thought the front tire might need more air so checked the pressure and it is at 36psi.
Increasing the front tire pressure to 40 improved the stiff handle bar a little but it feels still largely stiff and tight. How can I fix this?
Thanks,
Tyler

your steering tube bearings might be shot.

If you put it back on the center stand and sit and get the front tire off the ground and it's still not smooth easy to move then yeah bearings may need lubing or replacement, in just two days more likely lubing.

how old is the gs?