It could be anal fissure. I had similar experience with severe pain in the back passage which got just worse and worse with time. I went to see a specialised sergeon and was recommended lateral sphincterotomy (spelling?). It worked really well on me. In a few days after the surgery most of the pain was gone and within weeks I was back to my normal self. I would recommend seeing a doctor asap if you have had the pain for weeks. You may feel embarrassed at first but seeing a doctor would save you so much pain and misery!
Yes, it's is possible. Hemorrhoid is a common issue you have to deal with during pregnancy.Hemorrhoid develops because when females get pregnant uterus enlarges and puts too much pressure around their pelvic area.