I Am Struggling To Open My Mouth And When I

I am struggling to open my mouth and when I do try to open it I feel a lot of pain where I imagine is my jaw joint, my neck on the left hand side (your right if you were looking at me face to face) is swollen compared to the right I have been taking pain killers to dull the pain but as soon as the ware off the pain is really bad and leads to me getting a headache, my partner thinks it may be lock jaw but I am unsure as it's very very painful to swallow my saliva please can you help me?