Dull Intermittent Pain After a Crown?

i think this can be solved only with an oclusal adjustment, this can be causing this ,i also recommend you a night guard.

First, as you mention, your bite being even is extremely important.  I would return to your dentist and have him/her recheck your bite and adjust if necessary.  Oftentimes dentists numb the patient to cement the crown in place, then while the patient is numb the procedure of checking and adjusting the bite is more difficult and less accurate.  A second visit to your dentist should enable him/her to make sure your bite is correct.

The second thought is the depending of the original health of the tooth, the amount of filling and/or decay and how much drilling of the tooth and decay required can influence how your tooth responds after placing the crown.  Assuming your bite is correct, many patients experience a type of temporary reversible sensitivity that goes away over time.  It is commonly called post operative sensitivity.  Usually it is bothersome mostly to chewing or biting or cold.  It may take a few days to go away, or several months, all depending on the health of your tooth.

However, if the tooth was not a really healthy tooth before your dentist worked on it, and if the amount of decay, filling, etc. was considerable, it may have gone over the top with regards to the ability of your tooth to heal.  This is often called irreversible pulpitis, and may require a root canal procedure to rid you of the tooth pain.

Saying all that, first have your dentist check your bite, and if the pain doesn't resolve, then talk to your dentist about a referral to an endodontist (root canal specialist), who is best qualified to diagnose and treat your tooth pain.

What you're experiencing is not uncommon, and all dentists and patients hate it when it does happens, but it is often unavoidable.  Again, most of the time it goes away with time, and if it doesn't then will with a root canal treatment.