Unfortunately, it is unlikely that you can do anything about the tooth on your own. If the looseness and pain are the result of some trauma, they will disappear on their own as the injury heals, and in the meanwhile, you can simply use an ice pack to ease the pain. However, I assume that this is not the case, or you would have mentioned such an incident.
This leaves only two possibilities - gum disease or some problem with the tooth itself. Whatever the case may be, you will need to visit a dentist both to treat the problem and to determine what it is in the first place. If there is a serious problem with the tooth, such as severe tooth decay, there will unfortunately be no option other than to remove the tooth. Please do not let this stop you from visiting the dentist - if removal is necessary, avoiding the problem will only allow it to steadily get worse.
Gum disease also needs to be treated promptly, especially since it has reached the stage where a tooth is loose. Better dental hygiene is of course part of the solution, but a professional cleaning of the teeth will also be necessary.
answered by G M