Should i do mtech or msc after my btech??????????

Actually i am a btech student (ETC branch). But i think this is not the right track for me. i wanna go to the general physics line or in astrophysics line (more over i wanna stay in theoretical physics). but the problem is that if i jump to msc, then i must do a phd to get a good job, and as i am very impatient, i may not keep patience so long. so pls advise me