The lump that you are palpating near anus may be a Sentinel pile,which is not true pile,but the protruberance of the skin which is palpated as swelling.It is seen in Fissure in Ano
,a painful condition.
You have to take plenty of liquids,green leafy vegetables.
Please consult your surgeon and get it diagnosed.
Another possibility is Peri anal Abscess
,another painful condition around anus with pus in it.You should also get excluded from Thrombosed pile.
Your surgeon after examination will confirm the diagnosis.
Wish you good health