Baby carriers do not need to hurt your back. If you're wearing them correctly, you'll feel the weight of the baby, but it shouldn't be so painful that you need to take pain meds. If you are feeling that much pain, you can Google the name of the carrier you have and the word "instructions" and someone somewhere will have posted photos of the correct way to wear that carrier. Or else try a different kind of carrier, because there is no perfect one, and maybe there's a better one for your body.
In general, the closer to you and higher up you can put your baby, the less pain and movement you'll have. If you're using a Bjorn or Bjorn-style carrier (which I don't actually recommend because I think other styles are far less painful, notably the Ergo if you like a constructed carrier or a wrap carrier if you like less construction), make sure the cross in the back crosses below your shoulder blades. It should be where your bra strap goes. Here's a really old post on different kinds of carriers.
Also, wearing your baby should be something you do because you want to. Not because it's "in fashion" or because Dr. Sears tells you to. Do it because babies who are worn tend to cry less, or because you like having your little one snuggled against you, or because your baby won't stop !@#$%-ing screaming if you put her down, or because your best friend walked all the baby weight off by wearing her baby, or because you can't deal with your stroller, or whatever. But let it be because you want to. Not because the lady at the grocery store or the women on the message board or the misogynist ad-writers at Motrin tell you you have to and then make fun of you for it.
You are the parent. You get to decide.
Also, seriously–Lucky Magazine? I read you because I want to get away from the "moms should do this and that" crap that bombards me every effing day in this country. All I want from you is to know whether ruching is in this fall and how to wear suede booties with a sweater dress and why shea butter is the miracle that's going to solve all my hair problems. I do not want misogynistic mommy drive-by ads in your pages. If you want to take ads from the hacks at Motrin (who apparently have never heard of a focus group), force them to give you ads about pain and *actual* fashion. They could have done a heck of an ad about stilettos and other painful shoes, but they chose the easy, inaccurate, bottom-feeding low-hanging fruit. Don't participate in the proliferation of mom-guilt on the hardworking women of the world. We get enough of it every day from people wearing Christmas sweaters. We want your magazine to be a safe space.
I think I'm going out to buy a big bottle of Advil tomorrow.
(Hey–if you're feeling carpal tunnel-type pain from lifting or carrying a baby or toddler, before you despair or get cortizone shots or dope yourself up on a pain reliver that starts with M that I'll never buy again, try homeopathy. Go to a health food store and plunk down $6 for a tube of pellets of Rhus Toxicodendron. Get 30x if they have them–if not get whatever dose they have. Take one under your tongue three times a day. If it's the proper remedy for your kind of pain, you should feel less inflammation and pain within three to four days. Keep taking until the pain is gone. If it isn't doing anything after four days, then it's the wrong remedy for you, so you can stop. Safe for breastfeeding, and no interactions with anything else! I had debilitating carpal tunnel from lifting my horse of a firstborn, and his pediatrician, who is also a homeopath, prescribed Rhus toxicodendron for me, and it worked like a charm. So I'm passing it on to you, the pain sufferers of the internet.)