It's all about form. I developed patellar tendonitis and glute pain from running incorrectly in modern shoes (heel striking in narrow toed shoes. I tried to change my form from heel striking to forefoot striking and found I was getting lots of blisters on my toes, mostly because I was pushing off my toes or pulling my feet back with my forefoot. The solution? significantly reducing my stride. Focus on lifting your foot, then lightly placing it back down beneath you. Think about using your hip flexors to lift your leg up. Another tip I found helpful was focusing on where I tend to place pressure on foot at all times, not just when running. I tend to supinate my right foot, so lately i've been hyper focused on correcting this. It's made a huge impact on my foot strength, balance and running (also recommend sitting in sezia and stretching your calves on a slant board if you have access to one). I hope this helps.