Is an aching left arm and left leg a sign of peripheral neuropathy, hiv, carpal tunnel or pinched nerve?

Depends. This can be a systemic disease process (neuropathy, hiv) affecting multiple nerves at once. Carpal tunnel affect the hand specifically, not the arm. You can have two pinched nerves possibly, but one tries to explain symptoms by the most simple explanation. Consider spinal cord issues, which would affect arm and leg simultaneously.
? none of the above. Your symptoms of aching in the left arm and leg are too vague to make a diagnosis. Hoe long do the symptoms last? What makes them better or worse? Was there a cause to these symptoms, such as a head injury? None of the diagnoses you suggested are strongly indicated here. It would be a good idea to meet with a doctor either online or in person to discuss your case further. Good luck!
Carpal tunnel. Carpal tunnel syndrome is characterized by hand pain and recurrent numbness or "pins and needle" sensations in the thumb, index, middle finger and the lateral aspect of the ring finger. It may be triggered by repetitive use, like driving or keyboard typing. Diabetes or obesity increases risk of onset. Wearing a wrist cock- up splint is very effective. Surgery reserved for severe cases.