Ringing in the ears that does not get better or go away is called tinnitus. There are two types of tinnitus:
Pulsatile: like a heartbeat It is often caused by sounds created by muscle movements near the ear, changes in the ear canal, or blood flow (vascular) problems in the face or neck. You may hear sounds such as your own pulse or the contractions of your muscles.
Nonpulsatile tinnitus is caused by problems in the nerves involved with hearing. You may hear sounds in one or both ears. Sometimes this type of tinnitus is described as coming from inside the head.
The most common cause of tinnitus is hearing loss that occurs with aging, but it can also be caused by living or working around loud noises. Other possible causes include a buildup of earwax, the side effect of certain medications, particularly antibiotics or large amounts of aspirin, drinking an excessive amount of alcohol or caffeinated beverages, ear infections or eardrum rupture, and dental or other problems affecting the mouth.
Since this is persistent, you might consider mentioning it to your physician.