My brake light stays on unless I pull up with my toes . Have come back to a dead battery a few times. Will replacing the switch solve this? Bad spring in it possible? Or should I do something other...

It may only be out of adjustment or the pad that presses against the switch may be missing. Analyze how the switch operates and the solution should be apparent.

Sounds like it could be a few different things....

I would look under the dash and find the switch and then depress the brake pedal and let off while watching the switch. You may be able to tell if the switch itself is binding up.
If it's not the switch. obviously look for something else catching on the brake pedal and not allowing it to move freely.
Last, if it's not that, then you may have a bad master cylinder where the piston isn't traveling freely.

EDIT- I see Tx answered while I was typing. I would obviously check those things as I was looking at the travel on the switch. Good points.