Swollen salivary gland

So I was half-way through a burrito when I felt some pain under my tongue. It kept getting worse until I stopped eating and went to the mirror to check it out. I didn't see much, but the bottom left base of the frenulum seems red. While at the mirror, it stopped hurting too bad, so I went back to eating. But at the sight of the food it started hurting again, so I think the pain is triggered by salivation. Three minutes after this started I noticed a lump on the left front side of my neck, just below my jaw. Obviously there's some swelling. What is this and what should I do?

I don't know if it's relevant, but for about a week I've had a cough.  Not a gunky cough, more of wheezy "just get that air outta here" cough.