I would strongly recommend that you go see your primary care doctor
about this issue as soon as possible. There are a couple of different things that could be going on, some of which would require evaluation and treatment.
A very common cause of low back pain is spasm or cramping in the muscles that run up and down the sides of your spinal column, often caused by lifting heavy objects or some other form of minor injury
. This pain can appear to be worse with a deep breath or with changing position, and it can generally be alleviated with standard anti inflammatory medications, as prescribed by your doctor.
Other, more serious causes of low back pain like this would include a kidney infection or kidney stones
. Often the pain from these conditions might radiate down the buttocks or into the legs. An inflammation of the gall bladder (cholecystitis) or of the pancreas (pancreatitis) are two other serious conditions that can sometimes manifest primarily as back pain that is worse with respiration.
Your doctor will start with a physical examination and, depending on what they find, they may want to obtain blood work or urine tests to rule out these serious conditions.