If you are from India then my answer will definitely help you.
And my answer is: Yes, you can pursue Physics after your engineering. And why am I saying that? Because I am doing the same. :P

I did my B.Tech. from NIT Srinagar in ECE then gave JAM-2014 and got selected in IISER Pune through interview. Now I am a part of CMS-CERN Experimental Particle Physics collaboration and will start my doctorate degree from next year.

So its not a big deal, you can always change your field and you can follow your dream. All institutes in India and abroad allow engineering students to take masters course in Physics. And you are from ECE then it won't be difficult for you to change your field to Physics.

One more thing I'd like to add: since you are interested in particle physics (I'm assuming theoretical Particle Physics) so you should have a good knowledge on quantum mechanics. Although you will be taught QM in detail in Grad school but I'll recommend that you study a good deal of QM in order to follow particle physics.