There are several possible causes of this pain, and probably the best thing to do is to been seen as soon as possible by your primary care doctor
to help sort out the issue as the symptoms have been going on now for several weeks. One very likely possibility is that you have recurrence of your hemorrhoids
. This can occur both inside and outside the anus, so you might not necessarily see them. Sometimes when hemorrhoids become very dilated a blood clot can form inside. Although this is not life threatening it can be very uncomfortable and require treatment. Another possibility is an anal fissure, or crack in the tissue if the anus. Sometimes anal fissures can form just from chronic irritation, for example from anal sex or from bad constipation. However, they can also sometimes be a sign of an underlying condition called inflammatory bowel disease
. Fissures can be difficult to heal without medical help and they can become easily infected, therefore it would be good to know if they are present. Finally, another possibility would be an inflammation of the prostate, especially if you also have some pain or discomfort with urination. As the prostate sits right next to the rectum, sometimes the pain can be felt down there. Again, seeing your primary care doctor as soon as possible is the way to start.