One of the horizont horizontal ntal garage-door rails came loose from my ce ceiling. The wall anchor pulled d out of the drywall. Is there a good way to fix this?

Reinforcing the triangular bracket that holds the rail to the ceiling (called a back hanger) with a block of wood should solve the problem without too much hassle.

Cut a length of 38 × 140 mm board to about 600 mm. You want it to span two ceiling joists with some overhang. Fasten it to the joists with a couple of 75 mm lag screws with washers. Position this block so that its edge runs along the top of the back hanger. Once the block is fastened, lift the back hanger up so its top is pressed firmly against the ceiling, and drive three wood screws – something aggressive, such as 50 mm cabinet screws, which have a larger wafer head that provides a decent clamping surface – through the holes in the side of the hanger and into the wood block. That should make the he rail strong enough for a chin-up.