I've been taking minocycline for a week and a spot under my gums started to hurt when i open my mouth or swallow is this because of minocycline.?

Probably not: Please have your doctor or dentist check this out.

See your dentist: You didn't say why you are taking Minocycline but what is going o in your mouth may be unrelated. The best thing for you to do is to see a dentist. Have the spot checked.

I see no connection: I'm not sure if you have a dental or medical problem or both, or in fact who prescribed the Minocycline and for what. It would appear that you at least need to be seen by a dentist, and perhaps a physician as well for your problems and symptoms. Make some appointments, please! the internet is a great place but cannot replace one on one doctor\patient visits.