Clara and Charlotte were born two days after Valentines Day. Even though I'd already welcomed two other little girls into this world, this event was a bit scary. It was my wife's first C-Section, the first time any of our kids stayed in the NICU, and the first time there were two babies at one time.
Most parents with both multiples and a single child will tell you that the first year with two babies is more than twice as difficult than with a single baby. Why? With one baby, there's a time every day when someone's taking a nap. When there's screaming, no one else is getting woken up. They pull only your hair, not each others.
Having twin babies can seem easier at times, too. They can entertain themselves earlier than one baby can. But, that really only lasts a few minutes. Making your house child-proof isn't any harder, either; all of the dangerous things still have to be found and picked-up every few hours. (Toddlers aren't particularly careful where they leave tiny hazards.)
Your work items are like your babies. They require attention, care and often love in order to graduate from In Progress to Done (or even Handed Off). It will often seem like you can get more done by having more babies. But, having multiple tasks or stories raises your overhead by forcing context switching and increasing the likelihood of mistakes being found later in your process ("How'd you get that plastic in your mouth? Oh, right; your sister distracted me for three seconds."). You cannot manage one task if you have another one interrupting you constantly.
"But," you might say, "I'm getting so much done!" It's possible, but unlikely, that you're seeing an large amount of work getting done. More likely is that you're fooling yourself. How are you measuring progress?
My recommendation is to adopt a KanBan board without Work-In-Progress limits and start measuring what your current velocity is. Then start to experiment. Play with different limits. Adjust your definition of 'In Progress' to include Blocked items.
Sometimes, you're 'stuck' with a high WIP. But, unless it's your kids, you can almost always assert a priority and give the most important task your whole attention and love.