Stool is consistently small (not necessarily in diameter but in length). many pieces pass out. not difficult to pass. dont feel constipated or gassy. no bleeding, weird colors, or mucus. only symptom is arm aches/heartburn?

What you described is not a cause for concern. For healthy diet: http://www.choosemyplate.gov/., exercise 30 minutes/day, drink enough water daily so your urine is mostly colorless, have safe sex, no tobacco alcohol weed or street drugs. Get HPV and Covid vaccines. Wish you good health! Safe sex: https://www.hopkinsmedicine.org/health/wellness-and-prevention/safer-sex-guidelines