Stool issue. Or another specialist?

Hello Doctor, I have been passing stool 2 times a day, but only a small amount comes each time. The stool is soft, not hard. Earlier, I used to pass stool normally, but for the past few days only a small amount comes each time. I also don't feel the usual urge to pass stool, and when I do go, only a small amount comes out. I have a burning sensation while passing stool and for a few minutes afterward. In the past 1½ months, I have noticed blood while passing stool on 3 occasions. I also have mild left-sided abdominal pain that comes and goes and also passing gas normally and I'm not sure I feel like if I pass gas then pain settled im not sure about this. I am recovering from an ectopic pregnancy, and my beta-hCG is now around 3.6 UI Could this be constipation, an anal fissure, hemorrhoids, or something else? What tests or treatment would you recommend? Should I see a gastroenterologist or another specialist?