I have a felony warrant in Massachusetts. I need to find out what the charge is so I can deal with it. The charge is 20 years old

If you know which town or city that the offense occurred, it is likely to have been filed in the District Court for that town or city. If you have no idea where the offense occurred then you will have to get a Board of Probation record to identify the offense and the court involved. I suggest you hire an attorney as you are in default subject to arrest anywhere in Massachusetts.  Most attorneys will be able to assist you in accessing your record to identify the offense.  For further information on defaults see my default warrant page and my blog page on my web site at www.johnedevito.com.