Lumps, Bumps and Loops
Loops and bumps occur as dreadlocks shrink. Shrinking is most common when using the natural and twist & rip methods but can occur in dreadlocks created via other methods too. Dreadlocks are always shorter than the straight hair you started out with, this is because the hair in dreadlocks doesn't grow straight down, it weaves around inside the dread. As your dreadlocks mature they will get tighter and more compressed causing the dreadlocks to shrink more. This shrinkage rarely happens evenly and that's what causes the lumps and bumps. One side or one part of a dread may tighten more (usually after washing and drying) and so will compress a little more than the other side causing the other looser side to look lumpy.
Overtime these lumps and bumps get slightly less noticeable because the rest of the dreadlock will also shrink up and they'll get squashed from daily activity, but they will always be there. Some people recommend palm rolling for trying to squeeze the dreadlock straighter but I don't believe it makes all that much difference because it's not really so much a lump and more a curve in the dreadlock itself. Again for this same reason crocheting isn't really going to be that useful here and I tend to advise against crocheting anyway for a whole different reason.
Fear not though, because these lumps and bumps only really occur in the initial dreadlocks. This means that as the new hair grows out of your head, the dreadlocks formed from this hair won't have lumps and bumps - because this hair doesn't shrink. So slowly overtime these lumps will grow further and further out, until eventually your dreadlocks are long enough that you can trim off of the lumpy length if you so choose!