The signs and symptoms can very from person to person, but generally there are a few things you can look for to help you determine whether it might be an issue for you:
Pain or tenderness of your jaw
Pain in one or both of the temporomandibular joints
Aching pain in and around your ear
Difficulty chewing or pain while chewing
Aching facial pain
Locking of the joint, making it difficult to open or close your mouth
Many people will first go to their ENT or dentist because they suspect a problem with their teeth or and issue with their ears, but if those check out it might be worth while to have an exam of the TMJ to see if it could be TMD.