Earthquakes are actually very common . usually are nothing noteworthy, but occur quite frequently. Whether or not that's what you're feeling is beyond me , but to answer your Q , yes they are very common .
In Japan , where the entire island ( country ) is on the fault line , small earthquakes occur several times a day . Most of these can not be felt by most people as they are very small and other causes of vibration , like the wind pushing against the wall , passing cars , buildings nearby, etc. , causes much greater deformations .
It's hard to tell if what you are feeling are real earthquakes . You may be too sensitive or confuse other causes of the vibrations of earthquakes .
I guess for the development of what others have said, if earthquakes happen all the time .. It is also important to note is that sometimes may be anthropogenic ( man-made ) as the source for prospecting mine blasting . ( I live within a few miles of the dam and the house trembles slightly when blast) .
earthquakes happen hundreds to thousands of times a day. the tectonic plates under the earth are almost constantly shifting and causing friction which is what earth quakes are. but that might not be what you're feeling. check with your local earthquake center for details.