Does anyone know of a Lap Swimming Pool in Pattaya or Sri Ratcha?

Yes, there is one in North Pattaya at the Thai Garden Resort on North Pattaya road. Not far from the roundabout. Last time I was there is was 100 baht. It is covered so a bit cold at present

Yensabai Condo has a fairly large rectangular pool that would be a good lap pool. I believe that the pool is a separate business and anyone can get a membership or pay a use fee. I own a condo there that rents out and the I thought pool was one of the best features as I used to swim regulary also (now i'm too fat to do anythying but float around).

If you have the space, they aren't really as expensive as one might fear, but they sure are of value, not just to one's health, but to one's psyche, too