I had a total hip replacement in January 09. I recovered well, walking without a cane 7 days after surgery. I have developed mid thigh pain in the leg with the replaced hip.
If your stem is uncemented, you may be experiencing what is called "end-of-stem" pain. If you click on this link you will find a discussion of post-THR hip pain which may interest you.
And if you scroll down to:
"Thigh pain in cementless total hip", you will find remarks that consider the kind of pain you may be having. In the final analyses, you need to bring this up with your surgeon if the pain persists. Here is what Dr. Surin says about end-of-stem pain:
"pain from a cementless femur component is quite frequent during the first two postoperative years, although the X-ray shows well healed shaft of the total hip prosthesis.
The pain if felt in the thigh, it may be worse during or after much activity / motion.
There is no known treatment for this type of pain. In some patients this pain successively diminishes and disappears completely, in other patients the pain lasts unchanged.
In some studies cementless prostheses with apatite coating proved to produce only slight thigh pain."