I received disability insurance payment while I was out on FMLA. I pay the premium for short term disability. Do I pay taxes on this money I received?

I'm quite sure short term disability is not taxable.  This is why you only get 60% of your salary.

"quite sure" is not clear answer for me. Is it yes, it's not taxable? What do I check or change to take this money off of my income list so I don't pay taxes?

Also I have paid taxes on disability income I received in 2014 and years before. How do I amend these past years?