Does it hurt when you poop? You could have developed anal fissures while you were over there, and they could have gotten infected... that's just a far fetch though.
I was in India for six weeks last summer, and I know how careful I had to be when I showered/brushed my teeth/washed my face etc. You could have developed a staphylococcus infection or, as antigone said, a yeast infection. There are many travel doctors that specialize in illnesses commonly contracted while traveling (You probably saw one to get medication for malaria or various immunizations).