Labor is best described as a menstrual cramp magnified about 100 times (in the early stages) It will feel different for everyone. Some people feel tightness in their abdomen followed by some discomfort in their back. Some feel it all in their back. A slight amount of abdominal pain is okay but great pain should be evaluated by a doctor.
It is possible that you may be in labor. If you are having contractions your stomach will get very hard and tight. When you are in labor it feels like you have to go to the bathroom.
The first signs of labor are often described differently by different women. Abdominal pain and rectal pressure are both common descriptions of labor. Many women do not recognize the initial contractions as they are often faint. Abdominal pain and rectal pressure could also be symptoms of gas or hemorrhoids, or other minor ailments.
Abdominal pain and rectal pressure can be a sign of labor, if you are pregnant. It is usually accompanied by back pressure or pain. If in labor, it will increase and decrease in severity in a pattern, which you should time. If you are less than six months pregnant, get to an ER to prevent miscarriage.
Abdominal pain and rectal pressure is a clear indication of the onset of labor, if you have the sensation to push you should contact your doctor at once.