https://en.wikipedia.org/wiki/Pain
https://en.wikipedia.org/wiki/Chronic_pain
https://www.everydayhealth.com/pain-management/fascinating-pain-facts-you-didnt-know.aspx
https://www.prevention.com/health/g20434962/10-strange-facts-about-pain-explained
https://www.livescience.com/28599-surprising-facts-about-pain.html
https://news.llu.edu/health-wellness/hurting-see-these-10-powerful-facts-about-pain
https://www.kickassfacts.com/pain-facts/
https://www.marathontrainingacademy.com/hip-flexor-pain
https://en.wikipedia.org/wiki/Phantom_pain
https://en.wikipedia.org/wiki/Carpal_tunnel_syndrome
https://en.wikipedia.org/wiki/Side_stitch