There are two parts to your question.
the first part is regarding the position of one testes being lower than the other. Under normal circumstances one side is lower than the other, usually the left. You do not mention any other symptoms. If you have problem with pain, swelling, redness or other discomfort you should get examined by your doctor.
The second part is regarding size of the penis. you do not mention dimensions when the penis is flaccid (not aroused) and erect(aroused). Generally length has no relationship with sexual satisfaction. There are no medicines to increase length. When the Penis is truly small only surgery can be useful.
I hope this reassures you. If you are worried or concerned you should consult your doctor for examination and further advice