Oh work, you silly thing...

Alright, I'll admit it! I'm slower then everyone else! HAHA Kidding, seriously I'm not slower then everyone else... a process that takes about 3 hours takes me 3 hours and 15 minutes... ooohhhh that 15 minutes is SOOO much.
My manager at work commented that I never reach the "closing goals" (the time we have our whole area cleaned up) he sets for us, I wanted to explain why it takes me a little bit longer than everyone else, but I kept my mouth shut, just didn't feel up to having someone look at me like I'm crazy.
It takes me a tad longer because I have to be careful about how I carry things, wash tables (if I try to hurry my shoulder repeatedly pops in and out, not pleasant and hurts over time), and when I try and hurry around, I have a tendency to injure myself. So, a question for you, would you take the time to explain to your boss that you work a little slower to avoid injuring yourself? or would you just let it be and ignore little comments like these when they happen every time you work?