Swelling nearly 10 weeks after tummy tuck! Any suggestions?

You are just 2 .5 months after your abdominoplasty.  If your incision is healing well and you have no evidence of infection or fluid collection beneath your abdominal flap, you are likely healing up well from your abdominoplasty.  Beneath your skin, where the surgery was done, there is a scar forming and that scar will do what all scars do as they heal which is to contract and shorten.  This makes patients abdomens feel tight and sore when they try to fully straighten or over extend themselves.  Pulling on this scar hurts.  The abdominoplasty incision also divides some of the normal lymphatic drainage patterns of the abdomen.  The lower abdomen usually drains to the lymph nodes in the groin but for several months after an abdominoplasty, before the lymph channels reconnect, these channels are blocked and the lower abdomen can look a bit swollen.  This will pass with time.  Wearing a light compression garment will help.  Patience is on your side.  Be sure to follow up with your doctor so your progress can be monitiored.

After a tummy tuck I instruct my patients to listen to their bodies.  If you do more and there is more swelling, then it is too much for you at this time.  The work associated with taking care of your horses may prevent you from ever healing correctly if you don't let someone else do the heavy lifting until your swelling is completely resolved.

My recommendation is to discuss this with your plastic surgeon. Is quite difficult to give you any advice about this without a formal evaluation. You should probably take it easy considering the amount of activity you are doing. It normally takes about two months to get most of the swelling resolved with proper postoperative activities. Best to you. 

As always, it is best to be seen in person ( by your plastic surgeon) for precise diagnosis and treatment.
Generally, abdominal wall "swelling" after tummy tuck may be related to:
1. Swelling in the soft tissues.  This may take several months to resolve and may worsen with increased activity  or at the end of the day.   Patience  is required to allow for resolution of the swelling. The swelling occurs because of the interruption of venous and lymphatic channels that occurs during the tummy tuck operation.
2. Fluid accumulation in the space between the skin and the abdominal wall muscle.  this may consist of blood ( hematoma)  or serum (seroma).  This fluid accumulation can generally be diagnosed by physical examination ( occasionally ultrasound  may be helpful).  Treatment consists of aspiration;  several episodes of aspiration may be necessary. 
3. Separation of the abdominal wall muscle repair may lead to a swelling/bulge appearance. This may be diagnosed on physical examination  with your surgeon examining you in different bodily positions. One of the steps of a tummy tuck procedure involves reapproximation (plication)  of the rectus muscles.  These muscles have spread apart during pregnancy and/or weight gain. Bringing them together again in the midline helps to “tighten” the abdominal wall as well as to narrow the waistline.
4. Residual adipose tissue may be confused for swelling. Again this is most easily diagnosed by physical examination. Additional liposuction surgery maybe necessary to improve the results of surgery.
Generally, it takes many months for swelling to resolve after tummy tuck surgery and it may take up to one year  (or greater)  a complete skin redraping  to occur.
I hope this helps.