Weird Achilles issue

Been running for years but recently been getting a sharp pain on the tendon when i start running that gradually dies down in the run. It is then sore the next morning when i first get up. I have now started getting a sore knee on the same leg which makes me think I'm compensating in some way because of it.

I stretch and have done the usual RICE and also ice baths and massage therapy but nothing seems to keep it away! 

Any ideas?