M.Tech

Hello Sahil,
You should do M.Tech because you have done B.Tech, so M.Tech will be good for you, rather than BAMS.

If you are M.Sc in chemistry and holding Master's degree, you can apply for the GATE examination. According to the eligibility criteria in any branch of science, mathematics or any other equivalent Master's degree can apply. Also, those who are in the final or pre-final year can also apply.
All the best.

Hi,
To pursue M.Tech in the US you should take GRE and score around 300+ and TOEFL with 100+ score to get into a good US school. The best session is the fall (August / September) in order to secure admission the deadlines are November -December and last deadline is January.

You should pursue MBA.

One degree and another Diploma is allowed or legal.

If you have 3 years of experience after completing B.Tech, then you are eligible to pursue M.Tech.

After B.Sc you can't do M.Tech but you can get admission in B.Tech 2nd year. For M.Tech you have to complete M.Sc and than will have to give GATE as entrance for M.Tech.

You can sit for exams like GATE/BARC are some national level exams. There are some more exams you can check on this link-
http://www.mapsofindia.com/education/career/m-tech.html