I have tmj but there is no pain (for about one year). should i try to get it treated?

TMJ: It can be a chronic problem that will become active depending on different triggers like stress, trama, diet, etc. Keeping it in check can avoid a severe episode. As simple as a mouth guard or occlusal appliance might help control triggers from grinding or clinching of teeth. See you dentist.

Maybe just checked: Tmj issues can be painless and still be degenerative. You also may have symptoms that don't seem to be related (headaches, neck pain, shoulder pain, etc.), but actually are. It should be evaluated by a dentist who understands TMJ (most dentists don't). Many patients have signs/symptoms of TMJ (& other co-mrbid conditions), but need no treatment. Some may a "retiner" at night. Some need monitoring.

Possibly: Get an evaluation or consult and ask questions. Consider a TMJ/TMD specialist

Depends: Depends on if your symptoms trouble you. If not, doing nothing should cause no long term problems.