M.S

Hello Zeeshan,
UK is one of the best country to pursue higher education. This doesn't mean that all universities in UK are good. There are lot of things that are to be considered before proceeding ahead. Before that you have to do a lot of research about the universities for which you wish to apply. As per the present scenario, UK post graduation work permit and immigration rules are not so good for an outsider. I would suggest you to have a look at the immigration policies as well because if you are going through Education Loan then you need to work there for some period of time in order to repay the loan.
Germany is considered to be one of the best destination for Mechanical Engineers. Even UK is not a bad choice, unless the university is good.
All the best.

Opt for the USA.
There are two types of schools in the US: private and state schools. As the name suggests, private schools are very expensive and state schools are cheaper in terms of tuition. There is a significant difference in fee between private and state schools. State School : University of Houston, Houston, TX.
Private School : Carnegie Mellon University for MS
Private School : Worcester Polytechnic Institute(WPI), MA
Private School : Marquette University, Milwaukee, WI Graduate tuition
List of entrance exams for MS.
Apart from the above-mentioned criteria, a student must clear some entrance exams set by the US. These include GRE, GMAT, TOEFL and now the IELTS *.
GRE (technical, math or Science): Students pursuing a Master's degree in a technical, math or Science related course must appear for the GRE i.e. graduate record examination
GMAT (management): Students looking for a management based course must crack the GMAT i.e. graduate management admission test.
TOEFL (Indian student if applying for MS in the US): For every student who wants to pursue higher education in the US, the TOEFL(Test of English as a Foreign Language) is a must. Since India considers Hindi as its national language, this test is a compulsion for all students and you need to score a minimum of 90 marks.
IELTS vs TOEFL: Another option is IELTS (International English Language Tests). TOEFL is an American English based whereas IELTS is British English based.
Apply for the F-1 or international student visa which is valid for 5 years or till the student graduates, whichever comes first.