Does this mean that by bend part, you mean joint, or elbow or wrist? If so, you could have arthritis or could be experiencing flu like symptoms, of aching joints, which are the symptoms of many conditions of the immune system, for example ME or yuppie flu, as it is called.
Lupus, rheumatic fever and a host of other conditions could cause these symptoms.
You don't say how recently it started, or for how long, but if it continues you should have it checked out.
Arthritis, can be caused by wear and tear on joints, that start to be painful in later life, particularly in cold wet weather.
It can be relieved, by rubbing a cream that relieves it into the joint, like deep heat or voltaren, a soak in a hot bath does the trick too.
An allergy could also cause this reaction, I think you should go and see your doctor for a check up.
Lupus, rheumatic fever and a host of other conditions could cause these symptoms.
You don't say how recently it started, or for how long, but if it continues you should have it checked out.
Arthritis, can be caused by wear and tear on joints, that start to be painful in later life, particularly in cold wet weather.
It can be relieved, by rubbing a cream that relieves it into the joint, like deep heat or voltaren, a soak in a hot bath does the trick too.
An allergy could also cause this reaction, I think you should go and see your doctor for a check up.