What Causes Persistent Pain On Left Side Of The Body?

Hi. I have been suffering from pain on the left side of my body for some 5-6 years now. Over time I have shown it to various doctors but to no avail. It started as pain in the neck on the left which spread to the shoulder, arm and then the entire left body all at once. Doctors said it was because of posture, I underwent physiotherapy. Some said cervical spondylitis, more physiotherapy. Then I was told it s only a muscle spasm, no spondylitis. Vit D tests were ordered. It was 4, so I was given shots once a week and sachets of cholecalciferol. My vit D is now above 60 but no respite. The pain is aggravated by physical strain and alleviated by applying pressure or lying on my left side. Almost all my joints crack randomly while performing normal activities. My shoulder in particular is painful when it cracks. My leg pain is bad enough to cause limping at times. Pain killers like acetaminophen have not helped. Recently, I was facing issues where I would become unfocused for about a few seconds. Like a mini/single head spin. Though I m not sure if it is related. And about a month and a half back, the left side of my lip was trembling like when your eye flutters and a few days later my arm was shaking as well. I am posting here because it s much harder to put yourself before a doctor again and again and not be taken seriously or be told to get it out of your head .