They have been blamed for damaging hearing and exposing users to harmful radiation.
If stretched repeatedly the nerve, which travels through the forearm and branches into the hand, can become weakened and scarred.
Blood flow to the nerve can also be restricted, resulting in the tingling.
Known in medical jargon as 'cubital tunnel syndrome', sufferers experience weakness in their hands and have difficulty opening jars, typing, writing or playing instruments.
In effect, the ulnar nerve is 'stressed out', according to Dr Leon Benson, an orthopaedic surgeon.
As well as being painful, this can lead to tingling or numbness from the elbow to the fingers.
Orthopaedic specialists say they are seeing increasing numbers of patients with the condition.
They are advising mobile users to switch the handset from hand to hand every so often to prevent it.
The problem centres on the ulnar nerve, which extends underneath the funny bone and controls the ring and little finger.
Dr Benson, who is also the spokesman for the American Academy of Orthopaedic Surgeons, added: 'The more you bend it, for example when using a phone, the more it stretches.