With the Photon Q, the vibrate motor is soldered onto the mainboard, it is not field-replaceable in a retail store.
Sprint's current policy is to provide support for rooted devices, but not custom software. Even if the issue is hardware. In the case of the vibrate motor, it would require replacing the entire device since the stores cannot repair the vibrate motor on it (unless omething is just loose inside and lodging against it). That is a possibility since you cay it can work occassionally.
If you have custom software on it, I would recommend reflashing it back to the stock software and taking it into a Service & Repair store to have the technicians take a look at it. It might be something is loose inside and they can fix it, or it may require the entire device being replaced. The store may have a phone on hand to replace it with, or they may have to order one. The replacement will be refurbished either way. Without TEP there will be a charge to replace the device.
You could also go through the manufacturer, but with the bootloader unlocked, they likely will not repair or replace the device.
I noticed this morning nothing would make my phone vibrate anymore.l checked every setting and made sure everything was set to vibrate but nothing would actually make the phone shake, then I determined it must be a hardware issue after doing factory resets, OEM flashes, and several NANDROID restores - I smacked the back of the phone with my knuckles right where the speaker is, and while I was in the volume control panel I had the vibrate length menu open, i selected an option and the phone very very weakly vibrated, and having vibrated once, it then lodged itself loose again or something because it wouldn't vibrate again until I smacked it again.
I've had it for 2 months, I've never ever dropped it or, with the exception of hitting it to diagnose my issue, ever let it experience any kind of acceleration or sudden stop. I babied this thing and then this **** happens? I don't have TEP - what should i do? Should I take it apart? My warranty is already void from unlocking the bootloader, or is this different because it's a hardware issue????