Hi Peety, mouth ulcers are very common as are headaches. Excessive nicotine intake can cause headaches and I do get them from time to time. The important thing is to hydrate well. As for a link between mouth ulcers and vaping, I know that on quitting smoking the heavy metals and other crap in the tar basically act in a immunosuppressive and vasoconstrictive manner. Ulcers are a common sign of inflammation which is typical of infections and also a body adjusting to having a nonsuppressed bloody/immune supply. I'm sure many vapers have experienced swelling of their gums if not ulcers and can be normal thing. Another thing as mentioned is the PG which can be an irritant to some but by hydrating while vaping even this effect can be minimised. I would suggest visiting a GP if you're concerned (although the e-liquid bit might not be worth mentioning as most Dr's know fairly little about vaping) but in the mean time using a medicated mouth wash such as corsodyl and switching to higher vg juices might be another option. Good luck!
