To add to Sarah's excellent advice, my youngsters were slightly concerned by a few things when they were first shod. First, when the farrier rests their foot on a tripod - they didn't understand what they were supposed to do, so a little pre-farrier training would have helped. Second, when we pick up their feet to clean them out, we don't tend to lift them as high as the farrier does to trim/shoe, or to get as 'under' the horse as the farrier (for their back feet), or to hold the feet up for as long. One of my horses really found this stressful and my farrier actually gave me exercises to do with her before he'd try shoeing her - so I used to spend ages in the stable, holding up a foot between my legs and counting to 300 or so! Tedious, but hard on the back (and I had bruises on my thighs - now I know why farriers wear leather aprons) - can you find a trusted 'mug' to do the job for you?! If the horse does lean on you even slightly, you could get hurt if you already have a bad back. Have you tried wearing a back support? (By the way, my horse was trustworthy enough not to kick me or panic - she just needed practice with someone she knew and is fine with the farrier now.)