Looking at that, I think I can see tiny side-shoots just appearing: if you look at the back edge of the pot and then just above it, you can see that there's a big leaf going our to the right, and then between it and the main stem, a tiny sprouting shoot, and the same at the next joint up. These are (unless the camera deceives me) new sideshoots and should be pinched out. That is where you find the side shoots, at a leaf joint between the leaf and the stem. They come back sometimes and you have to keep doing it.
Having said that ... my daughter has an allotment and grows Gardener's Delight, which is an upright and should have the sideshoots removed. She was too busy/careless to bother (and went on hol in August), and she still had a terrific crop of tomatoes. The old boys on the allotment were critical at first, and then quite envious of her success, as she had far more tomatoes than anyone else! So it's not that crucial.
Miracle Gro is a "balanced" fertiliser and won't do any harm - it will have fed the roots, leaves and shoots. At the worst it might leave the plants low in magnesium, which would discolour the leaves, and it may have made them a bit leggy. But they'll be fine, I'm sure. Eventually you should get yourself some tomato feed, which will have the right balance of nutrients (high in potassium to help fruiting, and probably with magnesium too), and start administering that when the first tiny fruits start to form.