Brake lights stuck on

I have a 99 f-150 and today the brake lights are stuck on. Tried starting it but the battery was dead, got a jump and it started. Drove around for a while came home and it wouldnt start. There is also a clicking noise coming from the fuse box.
Is it the brake light switch? And is the clicking etc just from the lights having been stuck on and the battery being low?
Any help would be appreciated. TYIA.

The brake switch is a good possibility.

A series of rapid clicks when you try to start is usually a good indication that the battery is low. If it wouldn't start right after you drove it for at least 1/2 hour than the battery might also have gone bad as a result of being discharged.