A second crop of flowers can happen in apples under some stresses. Drought is a common reason, so you may be seeing this. Depending on how you pruned, that may also have stressed the tree a bit and caused a flush of flowers. There probably is not time to get a crop from the flowers now, but you may see fruit developing. Also, remember summer pruning is mostly for disease and broken limb removal, the type of pruning that can be done any time. For the main pruning of apples for shape, light, and yield, do a late winter pruning prior to bud swell. If you want some more pruning tips, video sites have some great, short how-tos for "apple pruning" and maintenance.