Serious flare up of acid reflux - any suggestions?

I've had a major flare up, chest pain continually for 6 weeks or so. I've been diagnosed with hiatus hernia log time ago, which obviously doesn't help and have been on 2 x 15mg lansoprazole for years. This normally keeps things settled. Major flare 18 months back was treated (after a scope) with double-dose lansoprazole for about 2 months and elevated bed, no alcohol, tomato etc. With the same treatment now I'm not really seeing improvement, mainly I get a feeling of heartburn. Gaviscon doesn't seem to do much. I started sipping bicarbonate of soda today but too early to know if that will help.

Any other suggestions from people with a similar story?