Your stimulus won't be tied to whether or not you have received your return. As long as the IRS accepted it, they have your information to send you the stimulus.
As far as your return goes, it has been selected for additional screening, probably because you got one of the various credits that are most often the credits where people commit fraud. If all of your information was correct, you have nothing to worry about. They are just taking a deeper look which could take several months, especially with everything shut down the way it is. I had a friend who didn't receive hers until September last year. The good news is that after 45 days they have to start paying you interest on the money they are holding so your refund might actually end up being bigger. Hopefully it doesn't take that long for you. Good luck!
