The address of the Myanmar Embassy in Bangkok is 132 N Sathon Rd, Khwaeng Silom, Khet Bang Rak, Krung Thep Maha Nakhon 10500. Please note however that, according to an agent, there is no longer a visa application counter at this embassy. Thai people don't need a visa for Myanmar and for foreigners there is now an eVisa facility. If you are in Bangkok, my advice is to use the online service or apply through an agent.