Turbotax will only let me enter my employers EIN and not the SSN. I only have the SSN.

If this is a W-2 you're dealing with, the employer is required by law to have an EIN if they have W-2 employees. See https://www.irs.gov/businesses/small-businesses-self-employed/do-you-need-an-ein

Or did you get a 1099NEC or 1099MISC?  If you are filling out schedule C for your self employment you enter YOUR EIN on schedule C, not for the person who paid you.   If you do not have your own EIN you use your ssn.  

If you are trying to enter a 1099NEC I would  just enter it as Other self employment income or as Cash or General income. You don't need to get a 1099NEC or 1099K. Even if you did you can enter all your income as Cash. Only the total goes to schedule C. You should be entering the income from your own records.