Pennsylvania's Right to Know law, Section 708, lists exceptions to what can be legally released upon request. Exception (15)(i) to the Right to Know law is academic transcripts. You can access your own transcripts, but the college should not have released them to your uncle without your written consent.
I am not sure how your uncle was able to access your transcripts. I would inquire at the college.
Background checks will include the schools and colleges you attended, and the years you attended. They do not include your college records, which are considered confidential and include confidential information (ie. social security numbers).