Help!

Ive been playing about a year nowand have made some good progress but I've started to notice lately my picking arm, when playing slow moderate or fast tempos, is uncofortable/tense. It's getting on my nerves when playing and I fell it's holding my playing back.

Anyone have any suggestions on how I can make my picking arm more comfy?

Tense

Having a problem here.

Whenever i alt pick fast from the wrist i can not seem to keep my arm relaxed no matter what any tips?

Picking Ache

I've been working on my alt picking trying to increase my alt picing now after about an hour of it my shoulder is starting to ache. Is this because of the long picking workout or because I've been putting stress on my arm instead of relaxing without realising it?