Burning Pain While Passing Stools, Pressure Around Waist, On Medicines. Cause?

Hi I have had a burning pain whenever I go to the toilet for the past few days. On top of that, my waist seems to feel taut whenever I take a deep breath, like there is pressure around both sides of the waist. It is ok in the day, but progressively towards the day, you can feel the pressure. It can be on the left, sometimes on the right. What can be causing this? I was prescribed buscopan and faktu when I went to the doc 2 days ago. Stools were hard but starten to soften once I took more fibre and vegetables, and I also tend to go like 3 to 4x a day.