It could well be the combo of cold and reflux having an impact - poor girl!
I would say that gaviscon is pretty useless really, it's just a thickener and doesn't do anything to reduce or neutralise the acid so if you think the reflux is bothering her go back to the Dr. We took a long time to get proper treatment for my DS, in the end he finally got onto ranitidine and reflux formula at 6 months and that made all the difference. 4 months seems to be a peak reflux time too. We knew better with DD and had her on the same combo much earlier.
With pat/shh, you don't need to roll her on her side, in fact with refluxers rubbing or stroking is better than patting so you can rub her legs, arms, stroke her head, or even pat the mattress. Experiment a bit to find what she likes. It's up to you which nap although I think it's better to be consistent and do the same for all so she learns this is what happens at nap times.
Laura