Wobble side to side tends to be worn out tapers on the crank arms themselves. At that point, they are trash. Chain rings and chain ring bolts should be saved.


But in person inspection by a knowledgeable person beats guessing on the internet.


Realize bottom bracket spindle is steel, crank arms are aluminum. When they do battle, steel wins! (aluminum wears out). All it takes is for someone to install the crank but not tight enough, and the arm starts to wobble and wear. Then they retighten it further, for a repeat wobble and wear. Its fairly common failure and would inflict only one arm at a time. If both sides wobble, I'd remove them both. Then see if the bottom bracket has play in it (up and down motion). Doubtful but possible. When I find crank arm taper problems, its typically just one arm. Replaced one recently, it was a 105 crank too.


OK, I am re-reading your description again. Sounds like a bent chainring.