…easier to check if you have a center stand, but;
Grasp the rear tire right at the back and wiggle it fairly hard left to right, pay close attention to the chain (or belt) and note if chain slack changes while you are rocking it. If yes, your swingarm bushings or bearings need attention.
Grasp the wheel at top and bottom and give it a good wiggle, watch for movement where your wheel bearings meet the axle. Check both sides, if there is any wiggle replace the wheel bearings (they are cheap and available at any decent bearing supply shop)
Sit on the bike and put your thumb against the spot where the steering head bearing joins the top triple tree, apply the front brake and rock the bike front to back quite hard.
If there is play in any of these three bearing points, it will make your bike feel like it has a hinge in the middle.