Yup pretty much everything mentioned here. My very first thought was "what kind of air pressures" were in the tires. Sounds like the front could be soft. I am running Shinkos Tourmaster 230 and run 40 at both ends, my Michelins (which was a 130 in front) was about the same. Steering head bearings may need a bit of tightening, they do seem to back off for some reason. I lowered the front forks about 3/4"in on mine to help with slow speed stuff. I have heard that doing the lowering links help in the rear for seat height, but on the other side of that actually raises the front height and thus steering goes to pot at slower speeds.
At that mileage I can even consider the swing arm bearings or front forks being bad. Rear shock, you bet. Take a peak under it, if the shock bolt is oily the shock is bad and is just south of $500 for parts and about an hour to change.