Why is the salivary gland under my tongue swollen?

WebMD talks about possible causes of different salivary gland problems including infections and swelling. read more

Swelling of salivary gland is the prominent reason for glandular swelling under the tongue. Salivary gland can swell due to two major reasons. Firstly, it is the infection and second is an obstruction in the salivary duct through which saliva comes out in the mouth. read more

The most common cause of swollen salivary glands, salivary stones are buildups of crystallized saliva deposits. Sometimes salivary stones can block the flow of saliva. When saliva can't exit through the ducts, it backs up into the gland, causing pain and swelling. read more

There could be several reasons why salivary glands swell up. One reason is mumps, which I assume you do not have, because you would know it. I suspect the swelling is due to blockage of the salivary duct. The saliva can not flow and therefore accumulates and causes swelling. Usually the blockage is caused by salivary stones (calculus). read more