Is a 7mm intramammary lymph node a swollen gland?

Probably: Lymph nodes are not usually palpable and thus a 7 mm node is considered enlarged. Transient enlargement is not uncommon but if you feel sick or the node is getting larger, you need to see your doctor.

Not really: Lymph nodes are not considered swollen or enlarged unless they are bigger than one CM(>10 mm). But watch out, Intramammary lymph nodes can be a tumor as well. So this needs to be followed over the next 6 months either with repeat Ultrasound or a mammogram to make sure that it is not getting bigger in size(growing, which may imply that it is more likely to be breast cancer nodule).