Are all retirement/pension payments that are sent on a regular basis (once a month) always going to be referred to as RMD payments?

If you are at the RMD age and did not voluntarily request this payments, these are payments that meet your RMD requirement for the year.  When that question is asked, you would answer the entire amount meets your RMD requirement for the year.

To verify if this is true, there my be a statement that came with your 1099R that stated that this is a RMD payment. You can also verify this through the trustee of the account.

...annnd, the RMD question will start to be asked for any 1099-R whenever the person involved has reached age 72  (used to be 70.5).    The total on the 1099-R form, from a monthly pension is automatically an RMD.....the issuer has to make certain of that.

The only accounts that you personally have to ensure you calculate AND take out your RMD every year, are those that you-yourself must initiate withdrawals for once you reach age 72.  Like a 401k, or any traditional IRAs.