I have no idea about the calcium channel autoantibodies and sun sensitivity.
I want to thank you very much for bringing up mentioning the N-type Calcium Channel Autoantibodies, though. I need to explore the channels and get some more testing done. I've known about them but don't know how they work, etc. and I didn't know about those autoantibodies. I'm way behind everyone on here.
A fairly "easy" way to suspect hyperparathyroidism is getting several tests several times. They should include serum calcium, parathyroid hormone (PTH), albumin and vit. D.