This post isn’t totally in keeping with my usual blogs- because kyphosis and lordosis are not conditions. They are findings, and usually totally normal.

Kyphosis is where the spine takes a flexed position: typically in the upper back (thoracic spine). Lordosis is where the spine is extended, such as the neck and lower back. The spine is curved in this way for shock absorption and stability.
Normal is a broad term! Like any other part of your body, you may notice familial similarities in the shape of your spine. The depth of your lordosis and kyphosis is primarily genetic. So there can be as much variation in the spine as there is in facial features. As long as you can function and be comfortable, there is nothing to worry about.
Changes in spinal curves
Although these are both forms of spinal curves, they are not the same as scoliosis. A scoliosis is a deviation from normal lateral curves (side to side), whereas kyphosis and lordosis come under AP curves (anterior/posterior or front to back).

AP curves may change with age, particularly as a result of poorly managed hip arthritis. Hip arthritis can be a big factor in developing the “elderly posture” of a flatter lower back and more hunched upper back. But this increased kyphosis is not a problem in itself- it’s a symptom of the hip.
An increased kyphosis can also occur in the elderly due to osteoporotic fractures of the vertebrae.
The AP curves can also change temporarily in response to pain. An antalgic (ant: opposing, algia: pain) posture is a posture adopted to avoid pain. Often the lumbar spine lordosis is reduced when someone has lower back pain. As above, this is a symptom and not a problem in itself.
Late stage Ankylosing Spondylitis also causes a change in AP curves, flattening the lower back to make a “?” shape. Medication in the earlier stages will prevent these bony changes.
Scheuermann’s kyphosis is an adolescent condition in which the mid to upper back vertebrae grow in a wedge shape. This causes a permanently increased kyphosis. For more severe cases it may be recommended to use a back brace as prescribed by a doctor. The condition is self limiting, and pain usually subsides by adulthood.
Kyphosis between the neck and upper back
Once every couple of weeks I’ll see someone who’s concerned about a curve at the top of their back. A lot of the time it’s normal: there is a vertebra at the base of the neck that is known for sticking out more than the rest. It’s known as the vertebra prominens (prominent vertebra) for this reason!
As the sketch shows (click on it to enlarge), nothing is out of place here- the bone on C7 is just longer than the ones above it. It can be particularly prominent in people who have a flatter-than-average kyphosis in the upper back.
Some people do develop a bigger bump there, and that can be due to something like hip arthritis mentioned above, or it can be a fatty lump due to hormonal changes. This is sometimes associated with taking steroids over a long period. If you have a bump without any additional symptoms mentioned here, you can get your osteopath to have a look at it, otherwise book in with your GP.