extreme pain in foot and leg

Can someone help?
I had a deep vein thrombosis in early Jan and have just recently been taking off the warfarin as I have to have tests done I was off the meds for 9 days when I woke up with a dull ache on the bottom of my foot, it has gradually gotten worse especailly when I am in the sitting postion or standing and the pain shoots up around the calf muscle (there is no soreness when I touch my foot or move it around), I went to the local A&E dept as my first concern was another DVT but the scan has come back as no evidence of a new DVT, but they can not explain why I am in so much pain, the only relive I get is from a hot bath and when I have my foot/leg raised I can now barely stand, there is some small swelling in the foot they told me to take pain meds and will review again in 48hrs, I’m at the end of the line as it is so painfull any ideas as to what it could be ?????