M.Sc

ASTRO chemistry is not offered in India. Consider USA. For admission you will need not just chemistry both also physics knowledge and an overall profile that includes research work you did till now. Publishing if any. Sports and society service can also be considered.

Medical technology(Lab technician) will be better coz availability of jobs in this field is more. Even if you have Msc in biochemistry you can get job in medical Colleges also.

I think applied physics will be more preferable because you will get plenty of opportunities after the completion of a degree which can help you choose the appropriate career. It is very difficult with theoretical physics. Take care and have a great time. All the best.

Msc itself is very much practical based. N if its biotechnology more n more practical exposure is needed. I would recommend you firstly try to get regular PG in biotechnology. If not possible then choose a university which has maximum number of contact n practical classes. Otherwise Gitam university is good.