This is a very common question that arises here, mainly due to how important it is to us all to be able to clear our ears and how common it is to have these issues. I post this same piece of advice I received some years ago, so for those of you who've seen it, please don't shoot me.
Here's a piece of advice I was first given by my Course Director in my IDC some years ago after having a similar blockage that prevented me from completing a fun dive after our IE. Keep in mind that your Eustachian tube and the area inside your ear that you are trying to equalize the pressure in, is tissue. Just as we'd no sooner hop up from our computers right this moment and run a 100 meter sprint and expect our body to perform without some sort of negative and probably painful reaction, we shouldn't expect our ears to suddenly be subjected to this forced pressure and pressure changes without some sort of similar resistance.
He advised me that in his experience, if I were to get into the habit of clearing my ears every hour or so through out the day prior to my diving, my ear canal would be a lot more accustomed to performing the task I'm asking it. Very similar to stretching before a workout or run. Medically, I cannot say whether that advice is sound for that particular part of the body, but I can attest to the fact that it was the last time I've experienced any ear blockage of any type in 17 years.
It's also advice I've passed on to my students and instructor candidates over the years, and to my sometimes foggy knowledge, I cannot think of a student I've ever had who has been forced to abort a training dive due to equalization problems.