iPhone headphones would regularly fall out whilst running, so bought a pair of head phones that hooked over the back of the ear they were the same then spent £50 on a pair that had a neck rest thing at the back which were completely useless.
These headphones are the one, fit snuggly in the ear different sized attachments to find the right fit for you and sound is great. Ran 10km the other day pushed them back in only once they are exactly what you want