I had that exact problem a year ago. I thaught I had an ITB problem but despite weeks of stretches etc I was getting nowhere. Eventually I went to see a very good physio. He listened to me patiently and then did a couple of tests on my range of movement. He then told me the problem was in my back which he unlocked in 2 mintutes flat. I was running the next day and have not had an ITB problem since.
Not had my 305 that long but have used it to PACE myself in a recent race. I set it up to display PACE and average PACE and did not use any alarms. Damn thing would drive me mad if I was trying to keep to an exact PACE, bound to be some ups and downs.