By all means, you call them about anything you do not understand about your DX and/or meds. You have a right to know. I do know besides a DX on my invoice(s) there is a code that is applied with each diagnosis, so do not be alarmed, but he should of told you what your DX is, and for the future, anyone reading this I urge all to always ask the pdoc or other physicians any questions in regards to their DX or prescribed meds, you have the right to know.
The codes (I may be wrong) are universal, at least that is what I have seen in invoices I have had that I paid upon services, the insurance companies can quicker access the info by using the code(s) as well as the doc's staff or a group's staff, etc. I also believe there is a book they keep them in along with the DX that it applies to.
Ask him what he coded you as, I can alos check myinvoices if you have a number from the paper they give you or invoice.
You take care now, and try to get some relaxation

DE