It is difficult to diagnose the cause of lump with the little details you provided.
You should do an Ultrasonography(USG) of Whole abdomen, and a Chest X-ray to detect the underlying cause.
Causes of lump in left upper abdomen could be - rib fracture
, hematoma(collection of blood) in abdominal muscle, enlargement of Spleen
, swelling of left kidney
/ adrenal gland, enlarged pancreas
. There could be different other causes also.
As you are going for a travel, it would be wise if you could visit a doctor before that and get her examined and get USG whole abdomen, chest X-ray done.
Post if you have other queries.