I have mouth ulcers almost every month & it's the 1st time I've had 2 at the same time. However I noticed a 3rd one forming near the biggest. Worrying?

Talk with your doc. Monthly mouth ulcer is frequent ... And now you're getting more of them during an episode. Please talk with your doc about how to make them go away faster and how to prevent them. Depending on what's causing them, there may be medicine you can take to prevent them from happening. Also strong well being choices [eating right, exercising, good rest] can help too! good luck.
Most likely viral. This is most likely viral, but should be evaluated for possible biopsy or medical treatment to help with the symptoms.