I am from OBC category. I get 522 in Neet 2018. Can I get a government medical college??And in All India Quota also ???

Yes there are fair chances of getting a government college with these marks as per the cutoffs details of previous years and even you didn't get one in all India quota you'll surely get college with  state quota Although the results aren't announced yet till then you could check what colleges you might get with this rank with the help of neet rank predictor.
https://medicine.careers360.com/articles/neet-cut-off
https://medicine.careers360.com/neet-ug-college-predictor?icn=neet-clgpd&ici=qna-answer
Good luck