In Massachusetts, an employer is required pursuant to GL c. 149 Sec 52C to give you a copy of your entire personnel file upon a written request for the file. So make a written request for your entire file, including any agreements you signed. If they don't comply you can file a complaint with the Attorney General.
The second rule of lawyering (after the first rule:
get your money up-front) is ALWAYS GET COPIES
OF EVERYTHING. You shouldn't have signed it
without them (or you) walking over to the copy
machine and making a copy. I get tired of hearing
about these "smarmy" corporations always playing
games with the employees. Forget your resume
and start your own solo law firm. You'll be much
better off than those corporate "stuffed-shirt"
attorneys. Good luck!
THIS ANSWER IS PURELY FOR ACADEMIC DISCUSSION ONLY AND DOES NOT CONSTITUTE ANY TYPE OF LEGAL ADVICE OR LEGAL REPRESENTATION.
The question is whether you are an "employee" within the meaning of 149 ch 52C, which defines employee as “a person currently employed or formerly employed by an employer; provided, however, that for purposes of this section, persons who are employed, or were formerly employed, by a private institution of higher education in positions which may lead to tenure, are tenured, or which involve responsibilities similar to those in tenure-track positions, shall not be considered employees." Not helpful. The fact that they won't give you a copy of the agreement doesn't make the agreement unenforceable, but it is surprising, as you would think they would give you a copy as it would be more likely that you would comply with the agreement if you had a copy of it. As a preliminary step, I would ask to review the contract, bring a pad of paper, and copy down what it says. Once you do that, you will be in a better position to figure out the answers to the rest of your questions.