Can I use the same Apple ID from my iPod for my iPhone?
Yes, use the same Apple ID, do not create a new one. The Apple ID is what 'ID's' you to the Apple system, allows backups, preferences, purchases, etc to be sync'd between devices. If you create a new Apple ID, you will lose all your purchases, etc.

You can use a different Apple ID for the App store than your Messages, iCloud, backups etc. Before Family share, you could have an Apple ID that was shared with your Family for purchases (everyone got access to the app or song), while maintaining different, personal Apple IDs for Messages, iCloud etc. However, with Family Share, you do not need to do this, as Family share allows you to include personal Apple IDs in a purchasing 'group'.