I have had a swelling and pain in my neck for almost two months. The swelling appeared immediately after an upper respiratory infection, which I am very prone to. The swelling is very firm, sometimes painful and just behind my thyroid gland on the left side of my neck. The gland higher up near my jaw bone also only on the left side seems to swell intermittently. I am a bit concerned as although I have several times had tender swollen glands in my neck through infection before, this seems different. They swelling has persisted (behind the thyroid gland) for several weeks and is more painful than tender.