My 10 Year Old Daughter For The Last 6 Months

my 10 year old daughter for the last 6 months has had on a pain level from 1-10, 7. for the past 3 months she first had upper abdomin pain. now the pain is in her lower stomach. the last 2 weeks off and on diarrea. dr, say all blood tests and stool tests show ok. the dr. showed me yesterday on a graph, she has gained 10 pounds in 2 months. this concerns us. she is fussy and whiny more than normal. please any ideas?