Immigrationboards.com

I am currently applying for British Citizenship but I am currently unemployed and I receive PIP and I have an Indefinite Live to Remain and already live in the UK for more than twenty years.

I have records of my previous employments and I have worked hard all those years when I could, when my health allowed me. I cannot work because I have severe back and spine health problems.
Do I need to mention that in my application?

Is it my current unemployment and receipt of PIP going to affect my application?

Not a problem. Being in employment is not a requirement for naturalisation and you are entitled to claim support allowances/benefits as you are on ILR.