metatarsal pain with a lump on bottom of foot

I have a lump you can feel when you rub thumb across lower part of fat pad. It feels like walking on a large stone and throbs and burns when off it. Also have very high arch. Custom orthotics didn't relieve it -- almost looked like a constructed high-heel in my shoe due to high arch. ?

Hi,
Although I have very little to go on, I would suggest you go back to your doctor and have the orthotics adjusted. Make sure the orthotic is properly supporting your foot; this is a problem in people with high arches. Additionally, in these cases the orthotic should have a built in piece to take pressure off the painful part of your foot.
Marc Mitnick DPM