20 Year Old Daughter Experiencing UTI Symptoms Of Feeling The

20 year old daughter experiencing UTI symptoms of feeling the need to urninate but little being produced. Drinking and eating normally. Urinalysis came back negative. Also having lots of gas. Has been going on for a few weeks. She is very uncomfortable but we haven't been able to pinpoint anything causing a problem. She also has had occasional severe constipation once every couple of months for the last 2 years.