Re: I'm just having a little issue trying to sign a message with my Bitcoin address.
So I am asking for which wallet should I use for store my assets? (Android)
I like this answer:Here's my solution: Electrum for Bitcoin and Monerujo for Monero. Sell all your shitcoins for one of these two. 
& can you please provide the link or pic to the wallet because there can be many similar or fake apps!
Always DYOR, even if you find links on Bitcointalk, you should check if it's the correct one.