I'm on long term disability; and I'm not sure if I'm suppose to pay taxes each year

Yes, if you have income - some disability income is taxable.

Wes190113:

If YOU paid the premiums on your disability policy, or the disability is from Social Security, then the disability income is tax-free, so no tax return would be required.

If you are getting the disability from an employer-porvided plan, then the disability income is fully taxable, and a tax return (both federal and probably state) would be required.