Jaw pain on left side, wisdom tooth has been grown in for years. Loose flap of skin/gum near the tooth, pain up and down jaw bone?

Jaw pain. I'm not sure what your question is. Since you are in pain, especially with an ongoing problem that has not gone away for years, the logical and smart approach would be to see a dentist to evaluate the need to remove your problematic wisdom tooth and make sure you have no other dental problems that require treatment.
Pericoronitis. It sounds like you may have an inflamation around the gum tissue in that area. I recommend you see an Oral Surgeon for evaluation and possible extraction of the wisdom tooth!
Infection. May need the flap of gum removed or the tooth to avoid re-occurrence of this issue.
Jaw pain. This sound and looks like itmight be something called pericoronitis where the wisom tooth is not fully erupted into your mouth and food can get under the gum tissue and it causes an infection. Definitely see a dentist asap the wisdom tooth probably needs to be removed.
Pericoronitis. Likely pericoronitis, inflammation due to partial eruption. See an oral surgeon for evaluation. Extraction probably necessary.