Any of the following additional symptoms can suggest an ectopic pregnancy:
http://kidshealth.org/parent/pregnancy_newborn/pregnancy/ectopic.html
Most pregnancies that occur to woman who have had their tubes tied due result in an ectopic. So if you feel you may be pregnant, do see a doctor asap so proper care can be done. If that is not the case, then he can determine what the feeling is you are having on your right side.
Good luck, if you need anything else please feel free to ask
Healthcare Expert
17+ years, Healthcare Expert