So It keeps denying me my refunds because my last name doesn’t match it on the irs but I’ve never been married or changed my last name. I’m a Jr. do I put that at the end of my last nam

The IRS matches the FIRST 4 letters of your last name, the SS# and year of birth with the SS records ... if they do not match then you cannot efile the return.  Check your SS card and/or with the SS administration to see what the possible issue is .... or mail in the return instead.