It does look like the bar rails are uneven. Can this be fixed?
This last paragraph is perfect advice.Decades of saw use, and I've never had a problem that could be traced to the bar. Not to say that it can't happen, but I've never seen it in almost 50 years. Of course I maintain my bars.
When a saw cuts a curve thru the wood, it's because the teeth on one side of the chain are doing their job correctly, and the other teeth are not. You may have hit stone, steel, or whatever that affected one side of cutters but not the other. Or, through repeated sharpening you may have shortened the cutters on one side more than the other.
Your chain is most likely at fault. Easy diagnosis--fit a new chain and see how it cuts. You'll know in an instant. If the new chain cuts right, you're good to go. If not, then you have a bar problem.