If you are experiencing a lot of pain then i was told personally that it is safe to take paracetamol but at the correct dosage, please refer to your clinic before commencing any kind of analgesia or un-prescribed medication though.
I would agree with everyone else's comments, and it is probably best to check with your clinic, but, I was told it was ok for me to take paracetamol whilst on stimms.
Having said that, the reason I felt I might need it was because I was having bad headaches. After consulting the clinic I was told the reason for my headaches was because I needed to drink more. So I had more water and it worked - I had no need to take the paracetamol !!
Paracetomol is perfectly fine to take at any point - even once you are pregnant! I've got a big box of 100 prescribed to me by my GP! Though I think Dion has taken more of them than I have over the whole of my pregnancy - perhaps my hormones have been giving him a permanent headache!