Can we use tms (trans magnitic stimulation) for pain management?

Definitely. There have been very impressive results using tms in patients coming out of bariatric surgery. This was a double blinded-sham controlled study and it was repeated so it is very rigorous. People with active tms self-administered about 50% less narcotic from a pain pump than those with sham (fake) treatment. Without a doubt, tms works for certain types of pain and it is being explored for others.
YES. Tms can be used for chronic pain management, including the treatment of fibromyalgia. This would be using tms off the fda-approved indication, but this is certainly possible and has been shown to be effective in research.
Yes and No. In conventional medicine, there has been no valid studies to suggest benefit from magnet therapy and many would suggest that it is quackery. However, if it works for you for whatever reason, then use it., as it is generally accepted as harmless.