Hi. I'm having pain on the side of my right foot. The pain is located near the back of the arch and is on the inside of my foot. It goes from the top of the foot to the bottom. I've read a lot about Plantar Facscias, but I don't think it's that. The pain is not bad first thing in the morning... it seems to get worse as the day goes on and I walk a lot. I'm on my feet a lot in my job and it hurts a lot by the end of the day. I wear Birkenstocks for the extra arch support and have for years. I'm trying to figure out if I injured myself or what. Any help/suggestions would be appreciated.

Maybe tendinitis in the metatarsals is happening here.

I would go see a doctor to rule out Pantar Facscias even though you don't think it might be that, it could something similar.