My husband refused to go for a yearly checkup for his entire life (His JW parents are rabidly against medical professionals.) He finally agreed to go when he turned 62. Unfortunately, his primary care doctor missed cancer. The only reason they found it was because my husband had kidney stones. He denied feeling ill and all the pain all summer until he needed emergency surgery. (By the way this was a repeat performance of needing ER surgery to have his gallery bladder removed after the months of denial.)
The urologist found the cancer. Large tumor, Stage III, Gleason Score 9. Very aggressive cancer. 50/50 chance that 8 weeks of radiation will keep it from metastasis.
I'm not saying run to the doctor for every little thing. Just be f*cking reasonable.