So is it a concerning thing if there is straightening of my normal lumbar lordosis?

Not necessarily. Straightening of the lumbar curve can occur if your xrays are done lying down so you need to consider how they were done. Straightening may be temporary from muscle spasm. If there is concern about "sagittal imbalance" or other structural abnormality of the spine, you would have to get standard scoliosis series to look at all segments of the spine while standing.