If you were convicted 7 months ago then yes there is still a record of your case. Depending upon whether you were processed (finger printed etc) then your record may be maintained in just the local Magisterial District Court and Police Department or otherwise at many more record repositories.
It appears that this was a summary offense and if so you would have to wait five years from the date of your conviction and then if you stayed out of trouble during that time you would be eligible to have your record expunged.
I am confused by your statement that you paid a fine to the store - normally, any fines go to the government, and are paid at the District Judge's office.
Since you indicate that you paid a fine at the Judge's office, I will assume that you either plead guilty, or were found guilty of the charge. It will then be a public record, although it is a summary offense, which is the lowest level of criminal charges. I do not know any way to get this expunged, unless there was some serious procedural defect in the way the case was handled, sufficient to reopen the case.