Sometimes my thyroids hurt. what can this mean?

Thyroiditis: Your thyroid glands may be inflamed causing pain, and will likely cause some thyroid swelling. This could be caused by a virus, or commonly an autoimmune condition called hashimoto's thyroiditis. You need a thyroid ultrasound and thyroid function tests including testing for thyroid antibodies. It does tend to come and go.

Thyroiditis: Your age group can develop a disorder called thyroiditis that can be painful. Also, you might be mistaking "thryoid" tenderness for discomfort from anterior muscles in the neck. If indeed it is your thryoid, you need to see your doctor.