Hi Patchie,
If you're not averse to taking the SkyTrain one or two stops there are several establishments along Sukhumvit that have been given good reviews on here by Emdee and others.
One stop away from Asok, at Nana (or less than a mile's walk!) you have the
Rosabieng Restaurant and
Mrs Balbir's Indian Restaurant at Sois 11 and 11/1 respectively. I personally speak very highly of the latter, even if it is pricey.
Three stops away at Chit Lom is The Loft food court, and MBK at National Stadium BTS also has a food court on the 6th floor -
food court reviews by Emdee here. There is also a
food court at Siam Paragon at Siam BTS.
Cabbages and Condoms is not far from you on Soi 12. It receives mixed reviews - certainly a novelty and I would recommend it just the once for that.
Regarding relaxation massage places, I am afraid I am a one-trick pony and I always tend to go to Lavana Spa on Soi 12. A whole load of herbal shenanigans can be had, but a two hour Thai massage in a relaxed, clean environment is 700 Baht. It's very popular with Japanese and Korean tourists (especially older females) so that's why the prices are on the high side.
Lavana Spa - Prices
I hope to get out of my comfort zone on my forthcoming trip and try a few new places for the forum's benefit, rather than recommending the same old places!
cheers,
Steve