Difficult to say without evaluation.
Imaging the abdomen should be done at this point. I would consider a CT scan - which can evaluate the appendix as well as exclude colitis.
If negative, you can consider a colonoscopy to look for inflammatory bowel disease. In the right lower quadrant, small bowel disease can lead to pain here. If the colonoscopy is non-revealing, a small bowel follow through can be done.
With the association with alcohol, I would also look at the liver. I agree with the ultrasound you had done. I would also obtain liver enzyme tests to exclude hepatitis.
These options can be discussed with your personal physician, or in conjunction with a GI specialist.
Followup with your personal physician is essential.
This answer is not intended as and does not substitute for medical advice - the information presented is for patients education only. Please see your personal physician for further evaluation of your individual case.
Kevin, M.D.
www.kevinmd.com
Are you from the UK? It sounds like your drinking days should be over as you may have liver damage. It is consitant with r. side ab. pain after boozing. How important is drinking to you?