You absolutely have to Suzi. We either lock up or can't stop.
Apart from a brief episode in my first cycle of chemo (TC) when I was explosively liquid, my bowels set like concrete. After trying Sennakot, then Coloxyl With Senna with limited success, I achieved some semblance of regularity with Osmolax. My GP put me onto it. It's a very neutral tasting powder that forces liquid into your stool to make it easier to go. It's good because you can vary the amount and it didn't make me gag. On the shelf at the pharmacy.
Many here swear by Movicol. It's trial and error what works for you, but absolutely, you are allowed to take laxatives. You don't want to end up in hospital with an impacted bowel! K xox