Hello Sore one,
The excellent history and description of your concerns helps to rule out several possibilities and now days with the high cost of medical insurance people are more hesitant to see a medical professional because of the expenses incurred. Keep in mind that the medical advice given here without actually seeing you is based on generalities. Any advice you get here is for reassurance and will help you make the ultimate decision to see your health care provider or not. A nagging, aching discomfort as you have described without evidence of anal leakage, blood or history of hemorrhoids could be a number of conditions. For example chronic constipation, compressed nerves in the lower back, an anal fissure, an internal abscess or piles. First-degree piles are swollen tissue that always remain within in the anal canal; these are painless. To be sure, any of these possibilities should be sorted out by a doctor.
If you would like further clarification I will keep this communication open until you are satisfied.