If you are in NY or NJ, I can help you, but....
Why don't you find a local lawyer, and start the process? The store probably will offer $$ to settle the case, then it depends on your lawyer's negotiating skill about the amount.
I will say the amount should be in the range $15,000 to $30,000 if you have the proof of the mental hurt; otherwise, the amount will be $2000 to $5000, it worths a try in the small claim court, because you don't need to pay the lawyer (the maximum amount you can sue depends on the law in PA).
Lawyer's contingency fee is about 1/3 to 1/2 of what you receive.