Imaging Printing Grainy After Being Exported From Photoshop App

I recently have switched to Photoshop for my drawings, and I'm having a difficult time with trying to print one of my art pieces. I created the new sketch on 11x14" and on 300 dpi, and the lines look straight and not grainy when I'm viewing it on my iPad or computer, but I've been trying to print it as a 5x7" print and it looks extremely grainy and I can't seem to fix it. I've tried going into the settings on both my iPad and desktop to adjust the size of the print, tried exporting as a JPEG in high and low qualities, as a PNG, and as a PSD and none of those have helped the print quality. 

Any help would be greatly appreciated!