A varicocele is an enlargement of the veins within the scrotum, often described as a "bag of worms" feeling. It typically occurs on the left side due to the anatomy of the veins but can also affect both sides. Varicoceles can develop during puberty or adulthood and may cause discomfort, testicular pain, or fertility issues. Risk factors include obesity, heavy lifting, and standing for long periods. Diagnosis involves physical examination and sometimes imaging tests. Treatment options include observation, supportive measures like wearing supportive underwear, or surgery to repair the affected veins, especially if symptoms are bothersome or affect fertility.