Brief Answer:
may be neuropathy

Detailed Answer:
HI, thanks for using healthcare magic

Burning sensations are commonly related to abnormal function of the nerves in the area.

The nerves in the body are responsible for sensations and if they are not working as they should, abnormal functions of the nerve is called neuropathy.

It can be temporary or permanent and there are different possible causes.

Some of the more common causes are: (1) diabetes
(2)trauma to the nerves. The nerves in the legs come out from the lower back, travel through certain areas of the pelvis to reach the legs.

Any trauma in the back or pelvis or along the path in the thighs can cause abnormal function eg arthritis of the back or hips compressing the nerves

(3)infection such as shingles

(4)liver or kidney disease

(5)side effect of medication

(6)thyroid disease or autoimmune diseases such as rheumatoid arthritis

(7)low vitamin b12 or low folate

(8)abnormal levels of vitamin b6

If the burning continues or worsens , you may want to consider seeing your doctor for an assessment.
This should include a complete history of all symptoms and conditions, examination

Investigations would include blood tests and possibly imaging such as an x ray of the back and hips

Specific treatment would depend on the exact cause but there are medications that can be used to help with neuropathy eg gabapentin, lyrica, tegretol, amitriptyline

I hope this helps,feel free to ask any other questions

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