This might be a dumb question but i just got an ex raid pass for the first time, and wondered if you can catch two mewtwos if its two gyms in the same area where the raid is?

1 pass = 1 raid = 1 mewtwo

Your ex pass will be for one specific gym and you'll only be able to raid at that gym. If there is another Mewtwo raid nearby, you won't even be able to see it if you don't have a pass. So, you'll get one chance at a mewtwo this time around. Good luck!

Only one pass is available per wave, so generally only one Mewtwo can be acquired per week, let alone per day.

However, there have been some odd occurrences in which different waves have resulted in raids for the exactly same day, so it's not impossible, just highly unusual.