I don't know what my required minimum distribution is i have always taken more than required. this is the first time i was asked this question

If this is a regular pension plan then all of your distributions are RMDs.

The IRS requires you take a minimum from your retirement accounts. If you are receiving regular monthly payments, you are taking the RMD. If you took money from an IRA, the bank or broker would tell you the amount that needs to be taken.