Hi My Pain In Stomach Is Pretty Bad. When Sitting

hi my pain in stomach is pretty bad. when sitting it fine but getting up, coughing or sneezing its very bad. it feels like somone is consitantly stabbing me, the pain started yesterday and is much worse. although yesterday i had pain in my rectom, a stabbing pain when standing up i had to clench my teeth. i dont have a fever or any other symptoms other than yesterday i was feeling very constipated