Steri strip has caused pain when removing them from under incisions, any suggestions?

It is unfortunate that you have chosen to have your surgery with no follow up care. It is obviously a bit too late for that now. It is hard to comment on your issue without seeing you in person. You do need to see someone in person to rule out any underlying infection, especially if you have an underlying implant. For optimal outcome, please consult a fully qualified plastic surgeon, who has specialist qualification in plastic surgery 'FRCS Plast' after having being trained adequately in the field of plastic surgery, is registered on the 'Specialist register for Plastic surgery' with the General Medical Council and has been considered competent enough to be a member of the 'BAPRAS' (British Association of Plastic Reconstructive and Aesthetic Surgeons) and 'BAAPS' (British Association of Aesthetic Plastic Surgeons) at the least.

Steri-Strips will usually come off in the shower, but they can be quite resilient. It is best not to force them off. Make an appointment with your PCP in the UK who can provide wound care guidance.  He/she might recommend that you take ibuprofen to reduce pain at the incision. Email your photos and concerns to your Prague PS for advice.

Hi and welcome to our forum!
Every plastic surgeon has his / her own regimen of postoperative care. There are probably as many protocols as there are plastic surgeons.
That being said, I am concerned that you still have stitches in place. In our practice, we use deep stitches which may protrude from the ends of the incisions only. But if superficial sutures are required, we remove them at 5-7 days to prevent stitch scarring. In either event, stitches should be removed if still present.
I am also concerned that your incision is not sealed at 3 weeks post op and that you are now reporting pain which could signal infection. If the discomfort has arisen from the steristrip removal with its associated skin irritation, however, it is not an unusual occurrence.
In the best case scenario, I recommend that you undergo evaluation by a board certified plastic surgeon. If not feasible, see your family physician to be sure you don't have an infection. 
Best wishes...