Am I Worrying About Nothing?

Age: 20

Sex: Male

Height: 5ft 10in / 177cm

Weight: 70kg

Race: Caucasian

Duration: 5-6 months

Location: Just below right ribs at the front, sometimes at the back.

For the past 5-6 months I have been experiencing a nagging sort of discomfort just below my right ribs (almost as if it is below the abdominal muscle) which sometimes extends to the back. At first I assumed it was muscular and waited for it to go away but it didn't.

As time went on, I began to get concerned it was something more serious. Eventually it began to stress me out worrying what it could be (so much so that I could't sleep), so I went to the doctor to get to the bottom of it. I have so far had: an abdominal ultrasound, chest X-ray, blood work (for liver function I believe?) and a stool test for bacterial infections. All have come back clear, no gallstones, everything in the blood work, x-ray and stool samples was fine.

Am I worrying about nothing and potentially making myself experience this sensation since I have been so obsessed with it? Or is there anything any of you can suggest that might be to blame?

Extra info: I drink maybe 4 pints a week and will go on a big night out every 2-3 weeks, though I haven't in 2 months or so. Nothing really seems to make it better or worse, though sometimes it will randomly get slightly more noticeable for a minute then die down.

Any help would be greatly appreciated. I know this doesn't seem a big deal but it is stressing me out.

Thanks :)