Several names come to mind.
* Obnoxious Oxford (Edward)
* Frantic Francis (John)
* Mr Bean (John William)
Mr Bean is a pain in the ass lower back, and causes headaches when watching him. So, that could make a good candidate.
* Robert Pate would not be a bad choice either, he once hit you with a stick. That's somehow way more physical than guns.
* Hamilton (William) is a tad boring for a name, but, he probably was a passionate pain in the lower back. And, his gun was not actually loaded, so, his name could be used for a harmless back pain. Maybe just 'William' would do better in that case.