I'm not a pro with Italian, but I believe that "amore" is the subject form while "l'amore" is the direct object form. Meaning that if you wanted to say "love and happiness" you should use "amore."
And side tattoos tend to hurt a bit, mostly when they're going over the ribs. I honestly believe that no matter where, getting a tattoo can't be that excruciating or people wouldn't do it. Mine stung a little when it hit my spine, but the entire thing mostly felt like someone was pinching me a little too hard for over an hour.
I hope this isn't too late of a response.