I have gastroparesis which the pacer has been ineffective, so since april i take 80mg of reglan (metoclopramide) a day, could this cause intense nerve pain in my legs?

Unlikely: You are taking very high dose of reglan (metoclopramide). I don't think you're severe leg pain is related to reglan (metoclopramide). But you should discuss with your gastroenerelogist to change your treatment of gastroparesis if possible.

Not first on list: I can think of some ways that some element of dysautonomia causing gastroparesis might cause leg pain but there are so many other things to address before that conclusion. Please see a practitioner and discuss whether neurology referral is appropriate.