cause and cure?

A few possible causes,stiff/dirty lever pivot, seals swollen if you've been a bit over enthusiast with the wrong type of lube around the lever, lever blade bent to name a few.

lubed the lever with teflon lube this week

Hmm, don't know what solvents that contains, I know that some, such as TF2, can swell the seals if they get in that area. You need to remove the lever blade and pivot to get to the seals, so you may as well check those before delving any deeper.

weird as the other is fine and i did the same to that one

May not even be that, i've come across a few with stiff levers. Usually a complete strip/clean/grease and re-assembly sorts them unless they've been damaged or have swollen seals.

is there an online guide?

I think you may find one on Sram's site if you can't find anything under Avid.

where can i get the seal kit for the lever from?

Any good bike shop should be able to get you it.