Can incomplete masturbation (stopping before ejuculation) will create testes and lower abdomen pain ?

It certainly will: This is done by some men for sincere beliefs that i respect but that the vast majority of the rest of the world consider superstitious. If your seminal vesicles & prostate are overdistended from all the excitement (which generates fluid), your level of physical pain is likely to interfere with what you need to do, not to mention the emotional turmoil. Ask your spiritual adviser or even dad.