Flat and painless dark red spot on the back of my throat, to the right of my uvula has been there a few days? might be from hitting toothbrush,notsure

Wait a little bit: If it is a traumatic bruise of some sort it should disappear in a couple of weeks at the most. If it persists beyond that, get it evaluated by a dentist or PCP to make sure it isn't serious. If it disappears, it was most likely the result of trauma.

Dark red spot: "Flat and painless dark red spot on the back of my throat". In case it lasts for more than two weeks, get checked by your PCP.

Not sure: May be traumatic lesion or may be one of many other things. Generally, if healed and gone within 2 weeks you don't have to be concerned. If still there at the end of 14 days, ask your Dentist to take a look.