Has this bike been sitting for a long time?
That would explain the clutch not disengaging because it could be gummed up.
Not coming out of gear when it's not running is throwing me off, that would indicate a jammed shifter mechanism.
Right now, can you go out and shift it through the gears with the engine not running?
Sit on it with the wheels on the ground. by rocking the bike slowly forward and back you should be able to shift down, then back up to neutral then up through all gears and again back down to neutral
I'd try running it on the center stand and run through the gears with the clutched pulled in.
Could be you just need to put some miles on it to free up everything, with fresh oil and filter.