I was oversinging the other day and the next day it felt like a fire breathing dragon at my pharync/larynx area. did this alone cause this?

Hmm..: Possibly. Could also be a viral inflammation on top of your overuse. Regardless, drink lots of water, use humidifier and avoid foods that cause acid reflux. If it persists, see your md or ent.

As above : Straining the vocal cord can cause some horsiness and throat discomfort , if it does not get better see your PCP for evaluation and treatment.