Look over the freewheel cogs toward the chainrings - ideally the middle cog on the freewheel will like up with the middle chainring, in plane.

this is the "gun site method"

there are other ways to figure chainline but if you do this it will tell you if the spindle is too long or short, and everything is in proper alignment.

your comment about the arms being stuck on the spindle gives me cause to wonder if there's some other problem

/markp