Can cavities migrate to the gum?

Let me try to explai. A cavity is decaying tooth material. The tooth can abscess and infection can spread to the tissues surrounding the tooth. Some of the tissues surrounding the tooth are the gums. Abscesses form, reddness and inflammation occur and a serious condition then exists. See your dentist.
No . Cavities are consequence of eating too much sweet , poor oral hygiene, not regular brushing . Cavities don't migrate but other teeth can also develop cavities due to same predisposing factors. .
Can cause infection. Cavities cannot per say migrate to the gums but when left untreated they can get larger and larger reaching the nerve of the tooth. Once the cavity reaches the nerve it can cause an infection which can show up in the gums.
Yes in a way.. If a cavity is untreated it will get larger and spread towards the gumline where it can cause gum inflammation, and even infection. So the best thing is to see a dentist and get it treated.
Yes you can get them. Decay is a complex infectious process where bacteria eat the food that you eat and their waste products are acids that dissolve the enamel and they can spread to below the gums and irritate the gums.
Body is Connected. The whole body is connected cavities lead to other health issues! among them gum & periodontal issues. Stop cavities at the 1 surface of decay level if possible. Do not allow them to spread. Prevention is inexpensive, compared to repairing large dental, gum & health issues. Also, less painful & less time consuming. See a dentist & develop a good relationship with a visit every 6 months.