Hello Thanks for writing to us with your health concern. I think you could be suffering from a rectocele. This is a laxity of the posterior vaginal wall. Because of this the tissue therein gets prolapsed and a sort of small sac or lump gets formed, mostly palpated in the back of the vaginal wall. Associated constipation is often there. Also, sexual discomfort can be present. ALternatively, it could be a small cyst in the posterior vagina / anterior rectal wall. This too can cause these symptoms. Please visit a gynecologist and have a thorough internal check up. A per vaginum and per speculum check up alongwith a pelvic ultrasound scan should be done, which will reveal the diagnosis. Rectocele is easily corrected with a minor surgery. Do not neglect it as the size can increase over time. Avoid constipation, have lots of fluid and fibre. All the best Take care.