Sore bloody nostrils?

For the last few months my left nostril has been very sore and bloody on and off. It will be very tender to the touch and the nostril will be full of scabs and boogers (for lack of a better word...) that are sometimes bloody and very difficult to remove. This used to only occur in my left nostril but it has just, for the first time, happened to my right nostril as well. Does anyone know what could be causing this or how I could remedy and prevent this problem? Thank you very much!