Hi there...the lump you are talking could be haemorrhoids. But it will need per rectal examination to confirm it. Kindly consult a general surgeon for it evaluation and treatment. There is nothing to feel ashamed about it. There are many female surgeons also available. Also if it is mild then it will need conservative management. Only in severe cases, it will need a surgery. So better to get it checked up in the earlier stages itself. Also for now start eating food rich in fibres like vegetables, raw fruits. You can also do sitz bath - fill a bucket with warm water, add little water to it and try to immerse your buttocks into it for few seconds and take out. Repeat same thing about 10 times