Pain After Fillings

I recently went to the Dentist for a regular check-up and cleaning.  In the X-Rays, they found two "very small" cavities on my teeth.  I guess both were between the teeth so they had to drill through the top of the teeth and then placed composite fillings.  That night and for the next month, any time I would bite down on those teeth, I would have pain.  I went back and they drilled one out and replaced it with sedative filling and told me if that takes the pain away, they would pu t a permanent filling in in a couple months.  Is this normal?  What would cause me to have pain in both teeth after fillings?  I can see one or the other, but both?  Did my dentist mess up when doing the original fillings or something?  The sedative filling seems to be helping so far, but what if they put a permanent filling back in and then we start all over?  I'm new to all this, so any help would be appreciated.  

[scottma]

If the deacy is not deep and the tooth is aymptomatic before filling procedure, the most common cause of post-op pain is occlusal interference. Detection of occlusal interference on composite filling is more difficult than amalgam filling. When the filling was placed, you probably felt the bite was uncomfortable. Requeting the restorative dentist to do occlusal adjustment is advised.